StringIO and compatibility with 'with' statement (context manager)

Question

I have some legacy code with a legacy function that takes a filename as an argument and processes the file contents. A working facsimile of the code is below.

What

Answer 1

you could define your own open function

fopen = open
def open(fname,mode):
    if hasattr(fname,"readlines"): return fname
    else: return fopen(fname,mode)

however with wants to call __exit__ after its done and StringIO does not have an exit method...

you could define a custom class to use with this open

class MyStringIO:
     def __init__(self,txt):
         self.text = txt
     def readlines(self):
          return self.text.splitlines()
     def __exit__(self):
          pass