code: def get_func_return_types(self, hsh: bytes) -> str:
          
          if not isinstance(hsh, (bytes, bytearray)):
              raise TypeError('The selector argument must be a concrete byte array')
          abi = self.get_abi(hsh)
          outputs = abi.get('outputs')
          return '()' if outputs is None else SolidityMetadata.tuple_signature_for_components(outputs)
docs: Returns the tuple type signature for the output values of the function
          associated with the selector ``hsh``.
  
          If no normal contract function has the specified selector,
          the empty tuple type signature ``'()'`` is returned.