code: def remove_label_from_pr(repo: GithubRepository,
                           pull_id: int,
                           label: str) -> bool:
      
      url = ("https://api.github.com/repos/{}/{}/issues/{}/labels/{}"
             "?access_token={}".format(repo.organization,
                                       repo.name,
                                       pull_id,
                                       label,
                                       repo.access_token))
      response = requests.delete(url)
  
      if response.status_code == 404:
          payload = json.JSONDecoder().decode(response.content.decode())
          if payload['message'] == 'Label does not exist':
              return False
  
      if response.status_code == 200:
          # Removed the label.
          return True
  
      raise RuntimeError(
          'Label remove failed. Code: {}. Content: {}.'.format(
              response.status_code, response.content))
docs: References:
          https://developer.github.com/v3/issues/labels/#remove-a-label-from-an-issue