code: def schema2jsonschema(self, schema):
          
          fields = get_fields(schema)
          Meta = getattr(schema, "Meta", None)
          partial = getattr(schema, "partial", None)
          ordered = getattr(schema, "ordered", False)
  
          jsonschema = self.fields2jsonschema(fields, partial=partial, ordered=ordered)
  
          if hasattr(Meta, "title"):
              jsonschema["title"] = Meta.title
          if hasattr(Meta, "description"):
              jsonschema["description"] = Meta.description
  
          return jsonschema
docs: Return the JSON Schema Object for a given marshmallow
          :class:`Schema <marshmallow.Schema>` instance. Schema may optionally
          provide the ``title`` and ``description`` class Meta options.
  
          https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#schemaObject
  
          Example: ::
  
              class UserSchema(Schema):
                  _id = fields.Int()
                  email = fields.Email(description='email address of the user')
                  name = fields.Str()
  
                  class Meta:
                      title = 'User'
                      description = 'A registered user'
  
              oaic = OpenAPIConverter(openapi_version='3.0.2', schema_name_resolver=resolver, spec=spec)
              pprint(oaic.schema2jsonschema(UserSchema))
              # {'description': 'A registered user',
              #  'properties': {'_id': {'format': 'int32', 'type': 'integer'},
              #                 'email': {'description': 'email address of the user',
              #                           'format': 'email',
              #                           'type': 'string'},
              #                 'name': {'type': 'string'}},
              #  'title': 'User',
              #  'type': 'object'}
  
          :param Schema schema: A marshmallow Schema instance
          :rtype: dict, a JSON Schema Object