code: def _parse_resource(resource):
          
          resource = resource.strip() if resource else resource
          if resource in {ME_RESOURCE, USERS_RESOURCE}:
              return resource
          elif '@' in resource and not resource.startswith(USERS_RESOURCE):
              # when for example accessing a shared mailbox the
              # resource is set to the email address. we have to prefix
              # the email with the resource 'users/' so --> 'users/email_address'
              return '{}/{}'.format(USERS_RESOURCE, resource)
          else:
              return resource
docs: Parses and completes resource information