class_docstr: A matrix group of linear (not affine) transformations with matrices having a specific dtype.
code: def inverse(self):
      inv_matrix = np.linalg.inv(self.affine[:-1, :-1])
      return self.__class__(inv_matrix, self.coords)
  
imports: import numpy
  from nipy.core.api import AffineTransform, CoordinateSystem
  from nipy.core.reference.coordinate_map import compose
  from nipy.core.reference.coordinate_map import product
label_desc: Use image node_id 4 for calling the MatrixGroup obj's underlying member method code with example usage: obj.inverse() and returns: self