code: def export_key(self, name, key_type, version=None, mount_point=DEFAULT_MOUNT_POINT):
          
          if key_type not in transit_constants.ALLOWED_EXPORT_KEY_TYPES:
              error_msg = 'invalid key_type argument provided "{arg}", supported types: "{allowed_types}"'
              raise exceptions.ParamValidationError(error_msg.format(
                  arg=key_type,
                  allowed_types=', '.join(transit_constants.ALLOWED_EXPORT_KEY_TYPES),
              ))
          api_path = '/v1/{mount_point}/export/{key_type}/{name}'.format(
              mount_point=mount_point,
              key_type=key_type,
              name=name,
          )
          if version is not None:
              api_path = self._adapter.urljoin(api_path, version)
          response = self._adapter.get(
              url=api_path,
          )
          return response.json()
docs: Return the named key.
  
          The keys object shows the value of the key for each version. If version is specified, the specific version will
          be returned. If latest is provided as the version, the current key will be provided. Depending on the type of
          key, different information may be returned. The key must be exportable to support this operation and the version
          must still be valid.
  
          Supported methods:
              GET: /{mount_point}/export/{key_type}/{name}(/{version}). Produces: 200 application/json
  
          :param name: Specifies the name of the key to read information about. This is specified as part of the URL.
          :type name: str | unicode
          :param key_type: Specifies the type of the key to export. This is specified as part of the URL. Valid values are:
              encryption-key
              signing-key
              hmac-key
          :type key_type: str | unicode
          :param version: Specifies the version of the key to read. If omitted, all versions of the key will be returned.
              If the version is set to latest, the current key will be returned.
          :type version: str | unicode
          :param mount_point: The "path" the method/backend was mounted on.
          :type mount_point: str | unicode
          :return: The JSON response of the request.
          :rtype: requests.Response