code: def _add_transitions(mcs, field_name, workflow, attrs, implems=None):
          
          new_implems = ImplementationList(field_name, workflow)
          if implems:
              new_implems.load_parent_implems(implems)
          new_implems.transform(attrs)
  
          return new_implems
docs: Collect and enhance transition definitions to a workflow.
  
          Modifies the 'attrs' dict in-place.
  
          Args:
              field_name (str): name of the field transitions should update
              workflow (Workflow): workflow we're working on
              attrs (dict): dictionary of attributes to be updated.
              implems (ImplementationList): Implementation list from parent
                  classes (optional)
  
          Returns:
              ImplementationList: The new implementation list for this field.