class_docstr: Class for Lie groups.
  
  In this class, point_type ('vector' or 'matrix') will be used to describe
  the format of the points on the Lie group.
  If point_type is 'vector', the format of the inputs is
  [..., dimension], where dimension is the dimension of the Lie group.
  If point_type is 'matrix' the format of the inputs is
  [..., n, n] where n is the parameter of GL(n) e.g. the amount of rows
  and columns of the matrix.
  
  Parameters
  ----------
  dim : int
      Dimension of the Lie group.
  lie_algebra : MatrixLieAlgebra
      Lie algebra for matrix groups.
      Optional, default: None.
  
  Attributes
  ----------
  lie_algebra : MatrixLieAlgebra or None
      Tangent space at the identity.
docstr: Identity of the group.
  
  Returns
  -------
  identity : array-like, shape={[dim], [n, n]}
      Identity of the Lie group.
docstr_tok: ["Identity","of","the","group",".","Returns","--","--","--","-","identity",":","array-like",",","shape=","{","[","dim","]",",","[","n",",","n","]","}","Identity","of","the","Lie","group","."]
code: def identity(self):
      """Identity of the group.
  
      Returns
      -------
      identity : array-like, shape={[dim], [n, n]}
          Identity of the Lie group.
      """
      raise NotImplementedError(
          "The Lie group identity is not implemented."
      )
  
imports: import abc
  import geomstats.backend
  from geomstats.geometry.invariant_metric import InvariantMetric
  from geomstats.geometry.manifold import Manifold
  from geomstats.geometry.matrices import Matrices
label_desc: Use image node_id 3 for calling the LieGroup obj's underlying member method code with example usage: obj.identity() without return types