def load(self, filename, create_if_missing=True):
        filename = Path(filename)
        if not filename.exists() and create_if_missing:
            self.load_pip_requirements()
            with filename.open("w") as f:
                f.write(yaml.dump(self.serialized, default_flow_style=False,
                                  encoding=None))
            self.filename = filename
            return self.save(filename)
        with filename.open() as f:
            for group, requirements in yaml.load(f.read()).items():
                for requirement in requirements:
                    self[group].add(Requirement.coerce(requirement))
        self.filename = filename
def _theme_widget_style(layout, widget_style):

        row = layout.row()

        subsplit = row.split(percentage=0.95)

        padding = subsplit.split(percentage=0.15)
        colsub = padding.column()
        colsub = padding.column()
        colsub.row().prop(widget_style, "outline")
        colsub.row().prop(widget_style, "item", slider=True)
        colsub.row().prop(widget_style, "inner", slider=True)
        colsub.row().prop(widget_style, "inner_sel", slider=True)

        subsplit = row.split(percentage=0.85)

        padding = subsplit.split(percentage=0.15)
        colsub = padding.column()
        colsub = padding.column()
        colsub.row().prop(widget_style, "text")
        colsub.row().prop(widget_style, "text_sel")
        colsub.prop(widget_style, "show_shaded")
        subsub = colsub.column(align=True)
        subsub.active = widget_style.show_shaded
        subsub.prop(widget_style, "shadetop")
        subsub.prop(widget_style, "shadedown")

        layout.separator()