code: def add_photo_to_observation(observation_id: int, file_object: BinaryIO, access_token: str):
      
      data = {'observation_photo[observation_id]': observation_id}
      file_data = {'file': file_object}
  
      response = requests.post(url="{base_url}/observation_photos".format(base_url=INAT_BASE_URL),
                               headers=_build_auth_header(access_token),
                               data=data,
                               files=file_data)
  
      return response.json()
docs: Upload a picture and assign it to an existing observation.
  
      :param observation_id: the ID of the observation
      :param file_object: a file-like object for the picture. Example: open('/Users/nicolasnoe/vespa.jpg', 'rb')
      :param access_token: the access token, as returned by :func:`get_access_token()`