Cannot generate client for object

[sargun]

Describe the bug
Endpoint is not generated

To Reproduce
Steps to reproduce the behavior:
Run pipx run openapi-python-client update --path ./specs/ally.yaml

Expected behavior
Endpoint is generated

OpenAPI Spec File

openapi: 3.0.0
info:
  title: Ally
  version: 1.0.0
servers:
  - url: 'https://api.tradeking.com/v1'
paths:
  /market/clock.json:
    get:
      operationId: clock
      description: This call will return the current state of the market, the time of the next state change (if the market is open), and the current server timestamp.
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                type: object
                properties:
                  response:
                    type: object
                    properties:
                      '@id':
                        type: string
                        format: uuid
                      status:
                        type: object
                        properties:
                          current:
                            type: string
                          next:
                            type: string

Desktop (please complete the following information):

• OS: [e.g. macOS 10.15.1]
• Python Version: [e.g. 3.7.8]

[dbanty]

Closing in favor of #162 just to deduplicate.