code: def get_default_branch(repo):
      
      url = "{}/repos/{}".format(GITHUB_API_BASE, repo)
      response = requests.get(url)
      if response.status_code == 200:
          api_response = json.loads(response.text)
          return api_response['default_branch']
      else:
          return 'master'
docs: returns the name of the default branch of the repo