function _getContexts(hook) {
  const ret = {};
  if (hook.hasOwnProperty('query')) {
    ret.query = hook.query;
  }
  if (hook.hasOwnProperty('document')) {
    ret.document = hook.document;
  }
  return ret;
}
Return the MongoDB namespace for this model as a string. The namespace is the database name, followed by '.', followed by the collection name.

#### Example:

    const conn = mongoose.createConnection('mongodb://127.0.0.1:27017/mydb');
    const TestModel = conn.model('Test', mongoose.Schema({ name: String }));

    TestModel.namespace(); // 'mydb.tests'

@api public