code: def delete_colormap(self, name=None):
          
          if name == None: name = self.get_name()
          if name == "" or not type(name)==str: return "Error: invalid name."
  
          # assemble the path to the colormap
          path = _os.path.join(_settings.path_home, 'colormaps', name+".cmap")
          _os.unlink(path)
  
          return self
docs: Deletes the colormap with the specified name. None means use the internal
          name (see get_name())