class_docstr: Summarize the fit of a linear regression model.
  
  It handles the output of contrasts, estimates of covariance, etc.
docstr: Return Mean square (error).
docstr_tok: ["Return","Mean","square","(","error",")","."]
code: def MSE(self):
      """Return Mean square (error)."""
      return self.SSE / self.df_residuals
  
imports: import numpy
  import scipy.linalg
  from nibabel.onetime import auto_attr
  from numpy.linalg import matrix_rank
  from nilearn.glm._utils import positive_reciprocal
  from nilearn.glm.model import LikelihoodModelResults
label_desc: Use image node_id 7 for calling the RegressionResults obj's underlying member method code with example usage: obj.MSE() and returns: unknown