def _remove_outer_indentation(src: str):
    """ Removes extra indentation from a source Python function.
        :param src: Source code (possibly indented).
        :return: Code after de-indentation.
    """
    lines = src.split('\n')
    indentation = len(lines[0]) - len(lines[0].lstrip())
    return '\n'.join([line[indentation:] for line in lines])