code: def lookup_email(args):
      
      email = args.email
      if email is None:
          email = gituseremail()
  
      if email is None:
          raise RuntimeError(textwrap.dedent("""\
              unable to determine a git email
              Specify --email option\
          """))
  
      debug("email is {email}".format(email=email))
  
      return email
docs: Return the email address to use when creating git objects or exit
      program.
  
      Parameters
      ----------
      args: parser.parse_args()
  
      Returns
      -------
      email : `string`
          git user email address