class_docstr: This is a mixin class to support scalar -> RGBA mapping.  Handles
  normalization and colormapping
docstr: set the colormap for luminance data
  
  ACCEPTS: a colormap
docstr_tok: ["set","the","colormap","for","luminance","data","ACCEPTS",":","a","colormap"]
code: def set_cmap(self, cmap):
      """
      set the colormap for luminance data
  
      ACCEPTS: a colormap
      """
      if cmap is None:
          cmap = get_cmap()
      self.cmap = cmap
      self.changed()
  
imports: import numpy
  from numpy import ma
  import matplotlib
  import matplotlib.colors
  import matplotlib.cbook
  from matplotlib._cm import *
label_desc: Use image node_id 9 for calling the ScalarMappable obj's underlying member method code with example usage: obj.set_cmap(cmap) without return types