class_docstr: Density estimation based on Gaussian Mixture Model.
  
  Args:
      n_components (int): Number of components used in the GMM.
docstr: Update the feature bank.
code: def update(self, features: Tensor, group: Any = None):
      """Update the feature bank."""
      del group
      self.memory_bank.append(features)
  
imports: from __future__ import annotations
  from abc import ABC, abstractmethod
  from typing import Any
  import torch
  from sklearn.mixture import GaussianMixture
  from torch import Tensor, nn
  from anomalib.models.ai_vad.features import FeatureType
  from anomalib.utils.metrics.min_max import MinMax
label_desc: Use image node_id 2 for calling the GMMEstimator obj's underlying member method code with example usage: obj.update(features, group) without return types