GetExtensionById.
        [Preview API]
        :param str extension_id:
        :param str version:
        :param str flags:
        :rtype: :class:`<PublishedExtension> <azure.devops.v5_0.gallery.models.PublishedExtension>`

def get_extension_by_id(self, extension_id, version=None, flags=None):
        """GetExtensionById.
        [Preview API]
        :param str extension_id:
        :param str version:
        :param str flags:
        :rtype: :class:`<PublishedExtension> <azure.devops.v5_0.gallery.models.PublishedExtension>`
        """
        route_values = {}
        if extension_id is not None:
            route_values['extensionId'] = self._serialize.url('extension_id', extension_id, 'str')
        query_parameters = {}
        if version is not None:
            query_parameters['version'] = self._serialize.query('version', version, 'str')
        if flags is not None:
            query_parameters['flags'] = self._serialize.query('flags', flags, 'str')
        response = self._send(http_method='GET',
                              location_id='a41192c8-9525-4b58-bc86-179fa549d80d',
                              version='5.0-preview.2',
                              route_values=route_values,
                              query_parameters=query_parameters)
        return self._deserialize('PublishedExtension', response)