code: def swagger_field(swagger_type="string", swagger_format=None):
      
      def decorator(field):
          setattr(field, SWAGGER_TYPE, swagger_type)
          setattr(field, SWAGGER_FORMAT, swagger_format)
          return field
  
      return decorator
docs: Decorator for an existing field type to coerce a specific swagger type/format.
  
      Usage:
  
          class MySchema(Schema):
               myfield = swagger_field(swagger_type="string")(fields.Foo())