def load(self, requirements_file=None):
        """Load or reload requirements from a requirements.txt file.

        :param requirements_file: if not given, the filename used from
            initialization will be read again.
        """
        if requirements_file is None:
            requirements_file = self.filename
            if requirements_file is None:
                raise ValueError("no filename provided")
        elif isinstance(requirements_file, text_type):
            requirements_file = Path(requirements_file)
        self.clear()
        with requirements_file.open() as f:
            self.loads(f.read())

        if isinstance(requirements_file, (text_type, Path)):
            self.filename = requirements_file
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()