code: def get_fields(cls):
          
          fields = {}
          for field_name in dir(cls):
              if isinstance(getattr(cls, field_name), Field):
                  field = getattr(cls, field_name)
                  field_name = field.field_name or field_name
                  fields[field_name] = field
          return fields
docs: Returns a dictionary of fields and field instances for this schema.