def _get_dev_port_var(backend, instance=None):
  port_var = 'BACKEND_PORT.%s' % str(backend).lower()
  if instance is not None:
    port_var = '%s.%d' % (port_var, instance)
  return port_var
Bind a callback for the given event sequence to the tag tagname.
dataset/ETHPy150Open GoogleCloudPlatform/python-compat-runtime/appengine-compat/exported_appengine_sdk/google/appengine/api/backends/backends.py/_get_dev_port_var--crossover with--dataset/ETHPy150Open francelabs/datafari/windows/python/Lib/lib-tk/ttk.py/Treeview.tag_bind