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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _expand_possible_file_value(self, value):
 """If the value is a file, returns its contents. Otherwise return the original value."""

    if value and os.path.isfile(str(value)):
      with open(value, 'r') as f:
        return f.read()
    return value