code: def validate_steps(self, request, workflow, start, end):
          
          errors = {}
          for step in workflow.steps[start:end + 1]:
              if not step.action.is_valid():
                  errors[step.slug] = dict(
                      (field, [six.text_type(error) for error in errors])
                      for (field, errors) in step.action.errors.items())
          return {
              'has_errors': bool(errors),
              'workflow_slug': workflow.slug,
              'errors': errors,
          }
docs: Validates the workflow steps from ``start`` to ``end``, inclusive.
  
          Returns a dict describing the validation state of the workflow.