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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_params(self, rdata):
 """ Returns a list of jsonrpc request's method parameters. """

        if 'params' in rdata:
            if isinstance(rdata['params'], dict) \
                    or isinstance(rdata['params'], list) \
                    or rdata['params'] is None:
                return rdata['params']
            else:
                # wrong type
                raise InvalidRequestError
        else:
            return None