code: def message(subject, message, access_token, all_members=False,
              project_member_ids=None, base_url=OH_BASE_URL):
      
      url = urlparse.urljoin(
          base_url, '/api/direct-sharing/project/message/?{}'.format(
              urlparse.urlencode({'access_token': access_token})))
      if not(all_members) and not(project_member_ids):
          response = requests.post(url, data={'subject': subject,
                                              'message': message})
          handle_error(response, 200)
          return response
      elif all_members and project_member_ids:
          raise ValueError(
              "One (and only one) of the following must be specified: "
              "project_members_id or all_members is set to True.")
      else:
          r = requests.post(url, data={'all_members': all_members,
                                       'project_member_ids': project_member_ids,
                                       'subject': subject,
                                       'message': message})
          handle_error(r, 200)
          return r
docs: Send an email to individual users or in bulk. To learn more about Open
      Humans OAuth2 projects, go to:
      https://www.openhumans.org/direct-sharing/oauth2-features/
  
      :param subject: This field is the subject of the email.
      :param message: This field is the body of the email.
      :param access_token: This is user specific access token/master token.
      :param all_members: This is a boolean field to send email to all members of
          the project.
      :param project_member_ids: This field is the list of project_member_id.
      :param base_url: It is this URL `https://www.openhumans.org`.