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 opengl_lamp_buttons(column, lamp):
    split = column.row()

    split.prop(lamp, "use", text="", icon='OUTLINER_OB_LAMP' if lamp.use else 'LAMP_DATA')

    col = split.column()
    col.active = lamp.use
    row = col.row()
    row.label(text="Diffuse:")
    row.prop(lamp, "diffuse_color", text="")
    row = col.row()
    row.label(text="Specular:")
    row.prop(lamp, "specular_color", text="")

    col = split.column()
    col.active = lamp.use
    col.prop(lamp, "direction", text="")