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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 get_possible_config_keys(self, action):
 """This method decides which actions can be set in a config file and what their keys will be. It returns a list of 0 or more config keys that can be used to set the given action's value in a config file. """

        keys = []

        # Do not write out the config options for writing out a config file
        if getattr(action, 'is_write_out_config_file_arg', None):
            return keys

        for arg in action.option_strings:
            if any([arg.startswith(2*c) for c in self.prefix_chars]):
                keys += [arg[2:], arg] # eg. for '--bla' return ['bla', '--bla']

        return keys