docs: def is_username_valid(username):
      """
      Check if a valid username.
      valid:
          oracle
          bill-gates
          steve.jobs
          micro_soft
      not valid
          Bill Gates - no space allowed
          me@yo.com - @ is not a valid character
      :param username: string
      :return:
      """
      pattern = re.compile(r"^[a-zA-Z0-9_.-]+$")
      return bool(pattern.match(username))