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 draw(self, context):
        layout = self.layout

        userpref = context.user_preferences
        edit = userpref.edit

        row = layout.row()

        col = row.column()
        col.label(text="Link Materials To:")
        col.prop(edit, "material_link", text="")

        col.separator()
        col.separator()
        col.separator()

        col.label(text="New Objects:")
        col.prop(edit, "use_enter_edit_mode")
        col.label(text="Align To:")
        col.prop(edit, "object_align", text="")

        col.separator()
        col.separator()
        col.separator()

        col.label(text="Undo:")
        col.prop(edit, "use_global_undo")
        col.prop(edit, "undo_steps", text="Steps")
        col.prop(edit, "undo_memory_limit", text="Memory Limit")

        row.separator()
        row.separator()

        col = row.column()
        col.label(text="Grease Pencil:")
        col.prop(edit, "grease_pencil_eraser_radius", text="Eraser Radius")
        col.separator()
        col.prop(edit, "grease_pencil_manhattan_distance", text="Manhattan Distance")
        col.prop(edit, "grease_pencil_euclidean_distance", text="Euclidean Distance")
        col.separator()
        col.prop(edit, "grease_pencil_default_color", text="Default Color")
        col.separator()
        col.prop(edit, "use_grease_pencil_simplify_stroke", text="Simplify Stroke")
        col.separator()
        col.separator()
        col.separator()
        col.separator()
        col.label(text="Playback:")
        col.prop(edit, "use_negative_frames")
        col.separator()
        col.separator()
        col.separator()
        col.label(text="Node Editor:")
        col.prop(edit, "node_margin")
        col.label(text="Animation Editors:")
        col.prop(edit, "fcurve_unselected_alpha", text="F-Curve Visibility")

        row.separator()
        row.separator()

        col = row.column()
        col.label(text="Keyframing:")
        col.prop(edit, "use_visual_keying")
        col.prop(edit, "use_keyframe_insert_needed", text="Only Insert Needed")

        col.separator()

        col.prop(edit, "use_auto_keying", text="Auto Keyframing:")
        col.prop(edit, "use_auto_keying_warning")

        sub = col.column()

        #~ sub.active = edit.use_keyframe_insert_auto # incorrect, time-line can enable
        sub.prop(edit, "use_keyframe_insert_available", text="Only Insert Available")

        col.separator()

        col.label(text="New F-Curve Defaults:")
        col.prop(edit, "keyframe_new_interpolation_type", text="Interpolation")
        col.prop(edit, "keyframe_new_handle_type", text="Handles")
        col.prop(edit, "use_insertkey_xyz_to_rgb", text="XYZ to RGB")

        col.separator()
        col.separator()
        col.separator()

        col.label(text="Transform:")
        col.prop(edit, "use_drag_immediately")

        row.separator()
        row.separator()

        col = row.column()
        col.prop(edit, "sculpt_paint_overlay_color", text="Sculpt Overlay Color")

        col.separator()
        col.separator()
        col.separator()

        col.label(text="Duplicate Data:")
        col.prop(edit, "use_duplicate_mesh", text="Mesh")
        col.prop(edit, "use_duplicate_surface", text="Surface")
        col.prop(edit, "use_duplicate_curve", text="Curve")
        col.prop(edit, "use_duplicate_text", text="Text")
        col.prop(edit, "use_duplicate_metaball", text="Metaball")
        col.prop(edit, "use_duplicate_armature", text="Armature")
        col.prop(edit, "use_duplicate_lamp", text="Lamp")
        col.prop(edit, "use_duplicate_material", text="Material")
        col.prop(edit, "use_duplicate_texture", text="Texture")
        #col.prop(edit, "use_duplicate_fcurve", text="F-Curve")
        col.prop(edit, "use_duplicate_action", text="Action")
        col.prop(edit, "use_duplicate_particle", text="Particle")