Colab 

import re
regex = r"([ \t]*)print[ \t]+(.*)"
replacement = r"\1print(\2)"


f = open("test.py")
for line in f:
    
    result = re.sub(regex, replacement, line)
    print(result,end="")
f.close()


print(1,2,3)
print("hello", "world")
if True:
	print(1,2,3)

	```
</div>
</div>
</div>



<div markdown="1" class="cell code_cell">
<div class="input_area" markdown="1">
```python
f = open("test.py")
for line in f:
    
    result = re.sub(regex, replacement, line)
    if(result != line):
        print(result.rstrip(), "\t# <-- ", line, end="")
    else:
        print(result, end="")

f.close()


print(1,2,3) 	# <--  print 1,2,3
print("hello", "world") 	# <--  print "hello", "world"
if True:
	print(1,2,3) 	# <--  	print 1,2,3

	```
</div>
</div>
</div>



<div markdown="1" class="cell code_cell">
<div class="input_area" markdown="1">
```python
f = open("test.py")
f2 = open("test-py3.py", "w")
for line in f:
    
    result = re.sub(regex, replacement, line)
    print(result, end="", file=f2)

f.close()
f2.close()

newf2 = open("test-py3.py")
for line in newf2:
    print(line, end="")
newf2.close()


print(1,2,3)
print("hello", "world")
if True:
	print(1,2,3)

	```
</div>
</div>
</div>



<div markdown="1" class="cell code_cell">
<div class="input_area" markdown="1">
```python