class_docstr: A mixin class to map scalar data to RGBA.
  
  The ScalarMappable applies data normalization before returning RGBA colors
  from the given colormap.
docstr: Helper for initial scaling.
  
  Used by public functions that create a ScalarMappable and support
  parameters *vmin*, *vmax* and *norm*. This makes sure that a *norm*
  will take precedence over *vmin*, *vmax*.
  
  Note that this method does not set the norm.
docstr_tok: ["Helper","for","initial","scaling",".","Used","by","public","functions","that","create","a","ScalarMappable","and","support","parameters","*","vmin","*",",","*","vmax","*","and","*","norm","*",".","This","makes","sure","that","a","*","norm","*","will","take","precedence","over","*","vmin","*",",","*","vmax","*",".","Note","that","this","method","does","not","set","the","norm","."]
code: def _scale_norm(self, norm, vmin, vmax):
      """
      Helper for initial scaling.
  
      Used by public functions that create a ScalarMappable and support
      parameters *vmin*, *vmax* and *norm*. This makes sure that a *norm*
      will take precedence over *vmin*, *vmax*.
  
      Note that this method does not set the norm.
      """
      if vmin is not None or vmax is not None:
          self.set_clim(vmin, vmax)
          if isinstance(norm, colors.Normalize):
              raise ValueError(
                  "Passing a Normalize instance simultaneously with "
                  "vmin/vmax is not supported.  Please pass vmin/vmax "
                  "directly to the norm when creating it."
              )
  
      # always resolve the autoscaling so we have concrete limits
      # rather than deferring to draw time.
      self.autoscale_None()
  
imports: from collections.abc import Mapping
  import functools
  import numpy
  from numpy import ma
  import matplotlib
  from matplotlib import _api, colors, cbook, scale
  from matplotlib._cm import datad
  from matplotlib._cm_listed import cmaps
label_desc: Use image node_id 2 for calling the ScalarMappable obj's underlying member method code with example usage: obj._scale_norm(norm, vmin, vmax) without return types