def set_default_style(self, colors='<STR_LIT>'):
colors = colors.lower()<EOL>if colors=='<STR_LIT>':<EOL><INDENT>self.style_sheet = styles.default_light_style_sheet<EOL>self.syntax_style = styles.default_light_syntax_style<EOL><DEDENT>elif colors=='<STR_LIT>':<EOL><INDENT>self.style_sheet = styles.default_dark_style_sheet<EOL>self.syntax_style = styles.default_dark_syntax_style<EOL><DEDENT>elif colors=='<STR_LIT>':<EOL><INDENT>self.style_sheet = styles.default_bw_style_sheet<EOL>self.syntax_style = styles.default_bw_syntax_style<EOL><DEDENT>else:<EOL><INDENT>raise KeyError("<STR_LIT>"%colors)<EOL><DEDENT>
Sets the widget style to the class defaults.

        Parameters:
        -----------
        colors : str, optional (default lightbg)
            Whether to use the default IPython light background or dark
            background or B&W style.