code: def send(self, from_, to, subject, text='', html='', cc=[], bcc=[],
               headers={}, attachments=[]):
          
          if isinstance(to, string_types):
              raise TypeError('"to" parameter must be enumerable')
          if text == '' and html == '':
              raise ValueError('"text" and "html" must not both be empty')
          return self._session.post('{}/send'.format(self._url), json={
              'from': from_,
              'to': to,
              'cc': cc,
              'bcc': bcc,
              'subject': subject,
              'headers': headers,
              'text': text,
              'html': html,
              'attachments': list(self._process_attachments(attachments)),
          }).json()
docs: Send an email.