title: NameError: name 'drive_service' is not defined Google API
body: <p>I want to upload a photo to google drive. 
  I can read the files that are on the drive. 
  But when I ad the uploading part, from line 49 to 55, I keep getting the same error.
  I keep getting the error "NameError: name 'drive_service' is not defined"
  I have every library imported but still doesn't work
  This is my code
  I've looked around but haven't seen a post explaining it.    </p>
  
  <pre><code>from __future__ import print_function
  from googleapiclient.discovery import build
  from httplib2 import Http
  from oauth2client import file, client, tools
  from apiclient.http import MediaFileUpload
  
  
  
  # If modifying these scopes, delete the file token.json.
  SCOPES = 'https://www.googleapis.com/auth/drive'
  
  def main():
      """Shows basic usage of the Drive v3 API.
      Prints the names and ids of the first 10 files the user has access to."""
      # The file token.json stores the user's access and refresh tokens, and is
      # created automatically when the authorization flow completes for the first
      # time.
      store = file.Storage('token.json')
      creds = store.get()
      if not creds or creds.invalid:
          flow = client.flow_from_clientsecrets('credentials.json', SCOPES)
          creds = tools.run_flow(flow, store)
      drive = build('drive', 'v3', http=creds.authorize(Http()))
  
      # Call the Drive v3 API
      results = drive.files().list(
          pageSize=10, fields="nextPageToken, files(id, name)").execute()
      items = results.get('files', [])
  
      if not items:
          print('No files found.')
      else:
          print('Files:')
          for item in items:
              print(u'{0} ({1})'.format(item['name'], item['id']))
  
  if __name__ == '__main__':
      main()
  
  file_metadata = {'name': 'photo.jpg'}
  media = MediaFileUpload('photo.jpg',
                          mimetype='image/jpeg')
  file = drive_service.files().create(body=file_metadata,
                                      media_body=media,
                                      fields='id').execute()
  print ('File ID: %s' % file.get('id'))
  </code></pre>