def colors(self, parameter_s=''):
        """Switch color scheme for prompts, info system and exception handlers.

        Currently implemented schemes: NoColor, Linux, LightBG.

        Color scheme names are not case-sensitive.

        Examples
        --------
        To get a plain black and white terminal::

          %colors nocolor
        """
        def color_switch_err(name):
            warn('Error changing %s color schemes.\n%s' %
                 (name, sys.exc_info()[1]), stacklevel=2)


        new_scheme = parameter_s.strip()
        if not new_scheme:
            raise UsageError(
                "%colors: you must specify a color scheme. See '%colors?'")
        # local shortcut
        shell = self.shell

        # Set shell colour scheme
        try:
            shell.colors = new_scheme
            shell.refresh_style()
        except:
            color_switch_err('shell')

        # Set exception colors
        try:
            shell.InteractiveTB.set_colors(scheme = new_scheme)
            shell.SyntaxTB.set_colors(scheme = new_scheme)
        except:
            color_switch_err('exception')

        # Set info (for 'object?') colors
        if shell.color_info:
            try:
                shell.inspector.set_active_scheme(new_scheme)
            except:
                color_switch_err('object inspector')
        else:
            shell.inspector.set_active_scheme('NoColor')