Help on class Popen in module subprocess:

class Popen(builtins.object)
 |  Execute a child program in a new process.
 |  
 |  For a complete description of the arguments see the Python documentation.
 |  
 |  Arguments:
 |    args: A string, or a sequence of program arguments.
 |  
 |    bufsize: supplied as the buffering argument to the open() function when
 |        creating the stdin/stdout/stderr pipe file objects
 |  
 |    executable: A replacement program to execute.
 |  
 |    stdin, stdout and stderr: These specify the executed programs' standard
 |        input, standard output and standard error file handles, respectively.
 |  
 |    preexec_fn: (POSIX only) An object to be called in the child process
 |        just before the child is executed.
 |  
 |    close_fds: Controls closing or inheriting of file descriptors.
 |  
 |    shell: If true, the command will be executed through the shell.
 |  
 |    cwd: Sets the current directory before the child is executed.
 |  
 |    env: Defines the environment variables for the new process.
 |  
 |    universal_newlines: If true, use universal line endings for file
 |        objects stdin, stdout and stderr.
 |  
 |    startupinfo and creationflags (Windows only)
 |  
 |    restore_signals (POSIX only)
 |  
 |    start_new_session (POSIX only)
 |  
 |    pass_fds (POSIX only)
 |  
 |    encoding and errors: Text mode encoding and error handling to use for
 |        file objects stdin, stdout and stderr.
 |  
 |  Attributes:
 |      stdin, stdout, stderr, pid, returncode
 |  
 |  Methods defined here:
 |  
 |  __del__(self, _maxsize=9223372036854775807, _warn=<built-in function warn>)
 |  
 |  __enter__(self)
 |  
 |  __exit__(self, type, value, traceback)
 |  
 |  __init__(self, args, bufsize=-1, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=<object object at 0x00000204D8CBB140>, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0, restore_signals=True, start_new_session=False, pass_fds=(), *, encoding=None, errors=None)
 |      Create new Popen instance.
 |  
 |  communicate(self, input=None, timeout=None)
 |      Interact with process: Send data to stdin.  Read data from
 |      stdout and stderr, until end-of-file is reached.  Wait for
 |      process to terminate.
 |      
 |      The optional "input" argument should be data to be sent to the
 |      child process (if self.universal_newlines is True, this should
 |      be a string; if it is False, "input" should be bytes), or
 |      None, if no data should be sent to the child.
 |      
 |      communicate() returns a tuple (stdout, stderr).  These will be
 |      bytes or, if self.universal_newlines was True, a string.
 |  
 |  kill = terminate(self)
 |  
 |  poll(self)
 |      Check if child process has terminated. Set and return returncode
 |      attribute.
 |  
 |  send_signal(self, sig)
 |      Send a signal to the process.
 |  
 |  terminate(self)
 |      Terminates the process.
 |  
 |  wait(self, timeout=None, endtime=None)
 |      Wait for child process to terminate.  Returns returncode
 |      attribute.
 |  
 |  ----------------------------------------------------------------------
 |  Data descriptors defined here:
 |  
 |  __dict__
 |      dictionary for instance variables (if defined)
 |  
 |  __weakref__
 |      list of weak references to the object (if defined)

Help on package multiprocessing:

NAME
    multiprocessing

DESCRIPTION
    # Package analogous to 'threading.py' but using processes
    #
    # multiprocessing/__init__.py
    #
    # This package is intended to duplicate the functionality (and much of
    # the API) of threading.py but uses processes instead of threads.  A
    # subpackage 'multiprocessing.dummy' has the same API but is a simple
    # wrapper for 'threading'.
    #
    # Copyright (c) 2006-2008, R Oudkerk
    # Licensed to PSF under a Contributor Agreement.
    #

PACKAGE CONTENTS
    connection
    context
    dummy (package)
    forkserver
    heap
    managers
    pool
    popen_fork
    popen_forkserver
    popen_spawn_posix
    popen_spawn_win32
    process
    queues
    reduction
    resource_sharer
    semaphore_tracker
    sharedctypes
    spawn
    synchronize
    util

SUBMODULES
    reducer

CLASSES
    builtins.Exception(builtins.BaseException)
        multiprocessing.context.ProcessError
            multiprocessing.context.AuthenticationError
            multiprocessing.context.BufferTooShort
            multiprocessing.context.TimeoutError
    multiprocessing.process.BaseProcess(builtins.object)
        multiprocessing.context.Process
    
    class AuthenticationError(ProcessError)
     |  Common base class for all non-exit exceptions.
     |  
     |  Method resolution order:
     |      AuthenticationError
     |      ProcessError
     |      builtins.Exception
     |      builtins.BaseException
     |      builtins.object
     |  
     |  Data descriptors inherited from ProcessError:
     |  
     |  __weakref__
     |      list of weak references to the object (if defined)
     |  
     |  ----------------------------------------------------------------------
     |  Methods inherited from builtins.Exception:
     |  
     |  __init__(self, /, *args, **kwargs)
     |      Initialize self.  See help(type(self)) for accurate signature.
     |  
     |  __new__(*args, **kwargs) from builtins.type
     |      Create and return a new object.  See help(type) for accurate signature.
     |  
     |  ----------------------------------------------------------------------
     |  Methods inherited from builtins.BaseException:
     |  
     |  __delattr__(self, name, /)
     |      Implement delattr(self, name).
     |  
     |  __getattribute__(self, name, /)
     |      Return getattr(self, name).
     |  
     |  __reduce__(...)
     |      helper for pickle
     |  
     |  __repr__(self, /)
     |      Return repr(self).
     |  
     |  __setattr__(self, name, value, /)
     |      Implement setattr(self, name, value).
     |  
     |  __setstate__(...)
     |  
     |  __str__(self, /)
     |      Return str(self).
     |  
     |  with_traceback(...)
     |      Exception.with_traceback(tb) --
     |      set self.__traceback__ to tb and return self.
     |  
     |  ----------------------------------------------------------------------
     |  Data descriptors inherited from builtins.BaseException:
     |  
     |  __cause__
     |      exception cause
     |  
     |  __context__
     |      exception context
     |  
     |  __dict__
     |  
     |  __suppress_context__
     |  
     |  __traceback__
     |  
     |  args
    
    class BufferTooShort(ProcessError)
     |  Common base class for all non-exit exceptions.
     |  
     |  Method resolution order:
     |      BufferTooShort
     |      ProcessError
     |      builtins.Exception
     |      builtins.BaseException
     |      builtins.object
     |  
     |  Data descriptors inherited from ProcessError:
     |  
     |  __weakref__
     |      list of weak references to the object (if defined)
     |  
     |  ----------------------------------------------------------------------
     |  Methods inherited from builtins.Exception:
     |  
     |  __init__(self, /, *args, **kwargs)
     |      Initialize self.  See help(type(self)) for accurate signature.
     |  
     |  __new__(*args, **kwargs) from builtins.type
     |      Create and return a new object.  See help(type) for accurate signature.
     |  
     |  ----------------------------------------------------------------------
     |  Methods inherited from builtins.BaseException:
     |  
     |  __delattr__(self, name, /)
     |      Implement delattr(self, name).
     |  
     |  __getattribute__(self, name, /)
     |      Return getattr(self, name).
     |  
     |  __reduce__(...)
     |      helper for pickle
     |  
     |  __repr__(self, /)
     |      Return repr(self).
     |  
     |  __setattr__(self, name, value, /)
     |      Implement setattr(self, name, value).
     |  
     |  __setstate__(...)
     |  
     |  __str__(self, /)
     |      Return str(self).
     |  
     |  with_traceback(...)
     |      Exception.with_traceback(tb) --
     |      set self.__traceback__ to tb and return self.
     |  
     |  ----------------------------------------------------------------------
     |  Data descriptors inherited from builtins.BaseException:
     |  
     |  __cause__
     |      exception cause
     |  
     |  __context__
     |      exception context
     |  
     |  __dict__
     |  
     |  __suppress_context__
     |  
     |  __traceback__
     |  
     |  args
    
    class Process(multiprocessing.process.BaseProcess)
     |  Process objects represent activity that is run in a separate process
     |  
     |  The class is analogous to `threading.Thread`
     |  
     |  Method resolution order:
     |      Process
     |      multiprocessing.process.BaseProcess
     |      builtins.object
     |  
     |  Methods inherited from multiprocessing.process.BaseProcess:
     |  
     |  __init__(self, group=None, target=None, name=None, args=(), kwargs={}, *, daemon=None)
     |      Initialize self.  See help(type(self)) for accurate signature.
     |  
     |  __repr__(self)
     |      Return repr(self).
     |  
     |  is_alive(self)
     |      Return whether process is alive
     |  
     |  join(self, timeout=None)
     |      Wait until child process terminates
     |  
     |  run(self)
     |      Method to be run in sub-process; can be overridden in sub-class
     |  
     |  start(self)
     |      Start child process
     |  
     |  terminate(self)
     |      Terminate process; sends SIGTERM signal or uses TerminateProcess()
     |  
     |  ----------------------------------------------------------------------
     |  Data descriptors inherited from multiprocessing.process.BaseProcess:
     |  
     |  __dict__
     |      dictionary for instance variables (if defined)
     |  
     |  __weakref__
     |      list of weak references to the object (if defined)
     |  
     |  authkey
     |  
     |  daemon
     |      Return whether process is a daemon
     |  
     |  exitcode
     |      Return exit code of process or `None` if it has yet to stop
     |  
     |  ident
     |      Return identifier (PID) of process or `None` if it has yet to start
     |  
     |  name
     |  
     |  pid
     |      Return identifier (PID) of process or `None` if it has yet to start
     |  
     |  sentinel
     |      Return a file descriptor (Unix) or handle (Windows) suitable for
     |      waiting for process termination.
    
    class ProcessError(builtins.Exception)
     |  Common base class for all non-exit exceptions.
     |  
     |  Method resolution order:
     |      ProcessError
     |      builtins.Exception
     |      builtins.BaseException
     |      builtins.object
     |  
     |  Data descriptors defined here:
     |  
     |  __weakref__
     |      list of weak references to the object (if defined)
     |  
     |  ----------------------------------------------------------------------
     |  Methods inherited from builtins.Exception:
     |  
     |  __init__(self, /, *args, **kwargs)
     |      Initialize self.  See help(type(self)) for accurate signature.
     |  
     |  __new__(*args, **kwargs) from builtins.type
     |      Create and return a new object.  See help(type) for accurate signature.
     |  
     |  ----------------------------------------------------------------------
     |  Methods inherited from builtins.BaseException:
     |  
     |  __delattr__(self, name, /)
     |      Implement delattr(self, name).
     |  
     |  __getattribute__(self, name, /)
     |      Return getattr(self, name).
     |  
     |  __reduce__(...)
     |      helper for pickle
     |  
     |  __repr__(self, /)
     |      Return repr(self).
     |  
     |  __setattr__(self, name, value, /)
     |      Implement setattr(self, name, value).
     |  
     |  __setstate__(...)
     |  
     |  __str__(self, /)
     |      Return str(self).
     |  
     |  with_traceback(...)
     |      Exception.with_traceback(tb) --
     |      set self.__traceback__ to tb and return self.
     |  
     |  ----------------------------------------------------------------------
     |  Data descriptors inherited from builtins.BaseException:
     |  
     |  __cause__
     |      exception cause
     |  
     |  __context__
     |      exception context
     |  
     |  __dict__
     |  
     |  __suppress_context__
     |  
     |  __traceback__
     |  
     |  args
    
    class TimeoutError(ProcessError)
     |  Common base class for all non-exit exceptions.
     |  
     |  Method resolution order:
     |      TimeoutError
     |      ProcessError
     |      builtins.Exception
     |      builtins.BaseException
     |      builtins.object
     |  
     |  Data descriptors inherited from ProcessError:
     |  
     |  __weakref__
     |      list of weak references to the object (if defined)
     |  
     |  ----------------------------------------------------------------------
     |  Methods inherited from builtins.Exception:
     |  
     |  __init__(self, /, *args, **kwargs)
     |      Initialize self.  See help(type(self)) for accurate signature.
     |  
     |  __new__(*args, **kwargs) from builtins.type
     |      Create and return a new object.  See help(type) for accurate signature.
     |  
     |  ----------------------------------------------------------------------
     |  Methods inherited from builtins.BaseException:
     |  
     |  __delattr__(self, name, /)
     |      Implement delattr(self, name).
     |  
     |  __getattribute__(self, name, /)
     |      Return getattr(self, name).
     |  
     |  __reduce__(...)
     |      helper for pickle
     |  
     |  __repr__(self, /)
     |      Return repr(self).
     |  
     |  __setattr__(self, name, value, /)
     |      Implement setattr(self, name, value).
     |  
     |  __setstate__(...)
     |  
     |  __str__(self, /)
     |      Return str(self).
     |  
     |  with_traceback(...)
     |      Exception.with_traceback(tb) --
     |      set self.__traceback__ to tb and return self.
     |  
     |  ----------------------------------------------------------------------
     |  Data descriptors inherited from builtins.BaseException:
     |  
     |  __cause__
     |      exception cause
     |  
     |  __context__
     |      exception context
     |  
     |  __dict__
     |  
     |  __suppress_context__
     |  
     |  __traceback__
     |  
     |  args

FUNCTIONS
    Array(typecode_or_type, size_or_initializer, *, lock=True) method of multiprocessing.context.DefaultContext instance
        Returns a synchronized shared array
    
    Barrier(parties, action=None, timeout=None) method of multiprocessing.context.DefaultContext instance
        Returns a barrier object
    
    BoundedSemaphore(value=1) method of multiprocessing.context.DefaultContext instance
        Returns a bounded semaphore object
    
    Condition(lock=None) method of multiprocessing.context.DefaultContext instance
        Returns a condition object
    
    Event() method of multiprocessing.context.DefaultContext instance
        Returns an event object
    
    JoinableQueue(maxsize=0) method of multiprocessing.context.DefaultContext instance
        Returns a queue object
    
    Lock() method of multiprocessing.context.DefaultContext instance
        Returns a non-recursive lock object
    
    Manager() method of multiprocessing.context.DefaultContext instance
        Returns a manager associated with a running server process
        
        The managers methods such as `Lock()`, `Condition()` and `Queue()`
        can be used to create shared objects.
    
    Pipe(duplex=True) method of multiprocessing.context.DefaultContext instance
        Returns two connection object connected by a pipe
    
    Pool(processes=None, initializer=None, initargs=(), maxtasksperchild=None) method of multiprocessing.context.DefaultContext instance
        Returns a process pool object
    
    Queue(maxsize=0) method of multiprocessing.context.DefaultContext instance
        Returns a queue object
    
    RLock() method of multiprocessing.context.DefaultContext instance
        Returns a recursive lock object
    
    RawArray(typecode_or_type, size_or_initializer) method of multiprocessing.context.DefaultContext instance
        Returns a shared array
    
    RawValue(typecode_or_type, *args) method of multiprocessing.context.DefaultContext instance
        Returns a shared object
    
    Semaphore(value=1) method of multiprocessing.context.DefaultContext instance
        Returns a semaphore object
    
    SimpleQueue() method of multiprocessing.context.DefaultContext instance
        Returns a queue object
    
    Value(typecode_or_type, *args, lock=True) method of multiprocessing.context.DefaultContext instance
        Returns a synchronized shared object
    
    active_children()
        Return list of process objects corresponding to live child processes
    
    allow_connection_pickling() method of multiprocessing.context.DefaultContext instance
        Install support for sending connections and sockets
        between processes
    
    cpu_count() method of multiprocessing.context.DefaultContext instance
        Returns the number of CPUs in the system
    
    current_process()
        Return process object representing the current process
    
    freeze_support() method of multiprocessing.context.DefaultContext instance
        Check whether this is a fake forked process in a frozen executable.
        If so then run code specified by commandline and exit.
    
    get_all_start_methods() method of multiprocessing.context.DefaultContext instance
    
    get_context(method=None) method of multiprocessing.context.DefaultContext instance
    
    get_logger() method of multiprocessing.context.DefaultContext instance
        Return package logger -- if it does not already exist then
        it is created.
    
    get_start_method(allow_none=False) method of multiprocessing.context.DefaultContext instance
    
    log_to_stderr(level=None) method of multiprocessing.context.DefaultContext instance
        Turn on logging and add a handler which prints to stderr
    
    set_executable(executable) method of multiprocessing.context.DefaultContext instance
        Sets the path to a python.exe or pythonw.exe binary used to run
        child processes instead of sys.executable when using the 'spawn'
        start method.  Useful for people embedding Python.
    
    set_forkserver_preload(module_names) method of multiprocessing.context.DefaultContext instance
        Set list of module names to try to load in forkserver process.
        This is really just a hint.
    
    set_start_method(method, force=False) method of multiprocessing.context.DefaultContext instance

DATA
    __all__ = ['Array', 'AuthenticationError', 'Barrier', 'BoundedSemaphor...

FILE
    c:\python36\lib\multiprocessing\__init__.py