class_docstr: Multivariate Gaussian distribution, specified by the mean vector
  and the Cholesky factor of its covariance matrix.
  
  Parameters
  ----------
  mu
      mean vector, of shape (..., d)
  L
      Lower triangular Cholesky factor of covariance matrix, of shape
      (..., d, d)
  F
      A module that can either refer to the Symbol API or the NDArray
      API in MXNet
code: def __getitem__(self, item):
      raise NotImplementedError()
  
imports: import math
  from typing import Optional, Tuple
  import numpy
  from gluonts.core.component import validated
  from gluonts.mx import Tensor
  from gluonts.mx.linalg_util import lower_triangular_ones
  from .distribution import Distribution, _sample_multiple, getF
  from .distribution_output import DistributionOutput
label_desc: Use image node_id 3 for calling the MultivariateGaussian obj's underlying member method code with example usage: obj.__getitem__(item) without return types