docs: def get_mailbox(self, email=None, email_hash=None):
          """
          Return list of emails in given email address
          or dict with `error` key if mail box is empty.
  
          :param email: (optional) email address.
          :param email_hash: (optional) md5 hash from email address.
          """
          if email is None:
              email = self.get_email_address()
          if email_hash is None:
              email_hash = self.get_hash(email)
  
          url = 'http://{0}/request/mail/id/{1}/format/json/'.format(
              self.api_domain, email_hash)
          req = requests.get(url)
          return req.json()