old_contents: ''' Define standard warning codes and messages for Bokeh validation checks.
  
  1000 : *MISSING_RENDERERS*
      A |Plot| object has no renderers configured (will result in a blank plot).
  
  1001 : *NO_GLYPH_RENDERERS*
      A |Plot| object has no glyph renderers (will result in an empty plot frame).
  
  1002 : *EMPTY_LAYOUT*
      A layout model has no children (will result in a blank layout).
  
  9999 : *EXT*
      Indicates that a custom warning check has failed.
  
  '''
  
  codes = {
      1000: ("MISSING_RENDERERS",     "Plot has no renderers"),
      1001: ("NO_GLYPH_RENDERERS",    "Plot has no glyph renderers"),
      1002: ("EMPTY_LAYOUT",          "Layout has no children"),
      1003: ("COLON_IN_CATEGORY_LABEL",        "Category label contains colons"),
      9999: ("EXT",                   "Custom extension reports warning"),
  }
  
  for code in codes:
      exec("%s = %d" % (codes[code][0], code))
  
  
new_contents: ''' Define standard warning codes and messages for Bokeh validation checks.
  
  1000 : *MISSING_RENDERERS*
      A |Plot| object has no renderers configured (will result in a blank plot).
  
  1001 : *NO_GLYPH_RENDERERS*
      A |Plot| object has no glyph renderers (will result in an empty plot frame).
  
  1002 : *EMPTY_LAYOUT*
      A layout model has no children (will result in a blank layout).
  
  1003 : *COLON_IN_CATEGORY_LABEL*
      Category label contains colons (will result in a blank layout).
  
  9999 : *EXT*
      Indicates that a custom warning check has failed.
  
  '''
  
  codes = {
      1000: ("MISSING_RENDERERS",         "Plot has no renderers"),
      1001: ("NO_GLYPH_RENDERERS",        "Plot has no glyph renderers"),
      1002: ("EMPTY_LAYOUT",              "Layout has no children"),
      1003: ("COLON_IN_CATEGORY_LABEL",   "Category label contains colons"),
      9999: ("EXT",                       "Custom extension reports warning"),
  }
  
  for code in codes:
      exec("%s = %d" % (codes[code][0], code))
  
  
subject: Add module level documentation for colon warning