def ParseString(value):
  """Parses a string if it is actually a True/False/None/Int value.

  Args:
    value: A string.

  Returns:
    True if the string matches one of 'True' and 'true. False if the string
    matches one of 'False' and 'false'. None if the string matches 'None'.
    An int if the string can be casted to an integer. Returns a string if
    nothing matched.
  """
  if value in ['True', 'true']:
    value = True
  elif value in ['False', 'false']:
    value = False
  elif value == 'None':
    value = None
  else:
    try:
      value = int(value)
    except ValueError:
      pass  # No sweat
  return value