old_contents: 
  import numpy as np
  import SimPEG
  import scipy.sparse as sp
  
  from .maps import SquaredSlownessMap
  
  class HelmBaseRegularization(SimPEG.Regularization.BaseRegularization):
  
      mapPair = SimPEG.Maps.IdentityMap
  
      @property
      def W(self):
          """Full regularization weighting matrix W."""
          return sp.identity(self.mesh.nN, dtype=np.complex128)#self.mesh.aveN2CC.T
  
new_contents: 
  import numpy as np
  import SimPEG
  import scipy.sparse as sp
  
  from .maps import SquaredSlownessMap
  
  class HelmBaseRegularization(SimPEG.Regularization.BaseRegularization):
  
      mapPair = SimPEG.Maps.IdentityMap
  
      @property
      def W(self):
          """Full regularization weighting matrix W."""
          return sp.identity(self.mesh.nN, dtype=np.complex128)
  
subject: Remove old comment.