code: def __get_vtt_angles(self, pvals, nvals):
  		
  		# https://www.khanacademy.org/math/trigonometry/unit-circle-trig-func/inverse_trig_functions/v/inverse-trig-functions--arctan
  		angles = np.arctan2(pvals, nvals)-np.pi/4
  		norm = np.maximum(np.minimum(angles, np.pi-angles), -1*np.pi-angles)
  		norm = csr_matrix(norm)
  		# Remove any weight from the NER features. These will be added later.
  		for key, value in self.B.items():
  			norm[0, key] = 0.
  		return norm
docs: Fit the angles to the model
  
  		Args:
  			pvals (array-like) : positive values
  			nvals (array-like) : negative values
  
  		Returns: normalized coef_ values