docs: def _validate_inputs(self, inputdict):
          """ Validate input links.
          """
          # Check inputdict
          try:
              parameters = inputdict.pop(self.get_linkname('parameters'))
          except KeyError:
              raise InputValidationError("No parameters specified for this "
                                         "calculation")
          if not isinstance(parameters, RipsDistanceMatrixParameters):
              raise InputValidationError("parameters not of type "
                                         "RipsDistanceMatrixParameters")
          # Check code
          try:
              code = inputdict.pop(self.get_linkname('code'))
          except KeyError:
              raise InputValidationError("No code specified for this "
                                         "calculation")
  
          # Check input files
          try:
              distance_matrix = inputdict.pop(
                  self.get_linkname('distance_matrix'))
              if not isinstance(distance_matrix, SinglefileData):
                  raise InputValidationError(
                      "distance_matrix not of type SinglefileData")
              symlink = None
  
          except KeyError:
              distance_matrix = None
  
              try:
                  remote_folder = inputdict.pop(
                      self.get_linkname('remote_folder'))
                  if not isinstance(remote_folder, RemoteData):
                      raise InputValidationError(
                          "remote_folder is not of type RemoteData")
  
                  comp_uuid = remote_folder.get_computer().uuid
                  remote_path = remote_folder.get_remote_path()
                  symlink = (comp_uuid, remote_path, self._REMOTE_FOLDER_LINK)
  
              except KeyError:
                  raise InputValidationError(
                      "Need to provide either distance_matrix or remote_folder")
  
          # Check that nothing is left unparsed
          if inputdict:
              raise ValidationError("Unrecognized inputs: {}".format(inputdict))
  
          return parameters, code, distance_matrix, symlink