code: def covariance_factor(self):
      if self.covfact in ["sc", "scotts"]:
          return self.scotts_factor()
      if self.covfact in ["si", "silverman"]:
          return self.silverman_factor()
      elif self.covfact:
          return float(self.covfact)
      else:
          raise ValueError(
              "covariance factor has to be scotts, silverman or a number"
          )
  
file_path: statsmodels/statsmodels/sandbox/nonparametric/kdecovclass.py
imports: import numpy
  from numpy.testing import assert_almost_equal, assert_
  import scipy
  from scipy import stats
  import matplotlib.pylab
label_desc: Use image node_id 3 for calling the gaussian_kde_covfact obj's underlying member method code with example usage: obj.covariance_factor() and returns: self, self, float