class_docstr: This is a mixin class to support scalar data to RGBA mapping.
  The ScalarMappable makes use of data normalization before returning
  RGBA colors from the given colormap.
docstr: Set the normalization instance.
  
  .. ACCEPTS: `.Normalize`
  
  Parameters
  ----------
  norm : `.Normalize`
docstr_tok: ["Set","the","normalization","instance",".","..","ACCEPTS",":","`",".Normalize","`","Parameters","--","--","--","--","--","norm",":","`",".Normalize","`"]
code: def set_norm(self, norm):
      """Set the normalization instance.
  
      .. ACCEPTS: `.Normalize`
  
      Parameters
      ----------
      norm : `.Normalize`
      """
      if norm is None:
          norm = colors.Normalize()
      self.norm = norm
      self.changed()
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import six
  import numpy
  from numpy import ma
  import matplotlib
  import matplotlib.colors
  import matplotlib.cbook
  from matplotlib._cm import datad
  from matplotlib._cm_listed import cmaps
label_desc: Use image node_id 9 for calling the ScalarMappable obj's underlying member method code with example usage: obj.set_norm(norm) without return types