docstr: Save fit into a .npz file
          
docstr_tok: ["Save","fit","into","a",".npz","file"]
code: def save(self, file):
      """Save fit into a .npz file"""
      np.savez(
          file,
          beta=self.beta,
          nvbeta=self.nvbeta,
          s2=self.s2,
          dof=self.dof,
          a=self.a,
          model=self.model,
          method=self.method,
          axis=self._axis,
          constants=self._constants,
      )
  
imports: import numpy
  import scipy.stats
  from nipy.algorithms.statistics.utils import z_score
  from ..utils import mahalanobis
  from .None import kalman
label_desc: Use image node_id 3 for calling the glm obj's underlying member method code with example usage: obj.save(file) without return types