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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 rpc(self, address, rpc_id):
 """Call an RPC and receive the result as an integer. If the RPC does not properly return a 32 bit integer, raise a warning unless it cannot be converted into an integer at all, in which case a HardwareError is thrown. Args: address (int):
 The address of the tile we want to call the RPC on rpc_id (int):
 The id of the RPC that we want to call Returns: int: The result of the RPC call. If the rpc did not succeed an error is thrown instead. """


        # Always allow mocking an RPC to override whatever the defaul behavior is
        if address in self.mock_rpcs and rpc_id in self.mock_rpcs[address]:
            value = self.mock_rpcs[address][rpc_id]
            return value

        result = self._call_rpc(address, rpc_id, bytes())

        if len(result) != 4:
            self.warn(u"RPC 0x%X on address %d: response had invalid length %d not equal to 4" % (rpc_id, address, len(result)))

        if len(result) < 4:
            raise HardwareError("Response from RPC was not long enough to parse as an integer", rpc_id=rpc_id, address=address, response_length=len(result))

        if len(result) > 4:
            result = result[:4]

        res, = struct.unpack("<L", result)
        return res