code: def inputs_valid(self, outputs=None):
          
          if self.operation == Transaction.CREATE:
              # NOTE: Since in the case of a `CREATE`-transaction we do not have
              #       to check for outputs, we're just submitting dummy
              #       values to the actual method. This simplifies it's logic
              #       greatly, as we do not have to check against `None` values.
              return self._inputs_valid(['dummyvalue'
                                         for _ in self.inputs])
          elif self.operation == Transaction.TRANSFER:
              return self._inputs_valid([output.fulfillment.condition_uri
                                         for output in outputs])
          else:
              allowed_ops = ', '.join(self.__class__.ALLOWED_OPERATIONS)
              raise TypeError('`operation` must be one of {}'
                              .format(allowed_ops))
docs: Validates the Inputs in the Transaction against given
          Outputs.
  
              Note:
                  Given a `CREATE` Transaction is passed,
                  dummy values for Outputs are submitted for validation that
                  evaluate parts of the validation-checks to `True`.
  
              Args:
                  outputs (:obj:`list` of :class:`~bigchaindb.common.
                      transaction.Output`): A list of Outputs to check the
                      Inputs against.
  
              Returns:
                  bool: If all Inputs are valid.