user: What is Index – U and how is it used in Blender Python scripting?

assistant: s.ToolSettings.use_gpencil_vertex_select_mask_stroke) - [use_gpencil_weight_data_add (bpy.types.ToolSettings attribute)](bpy.types.ToolSettings.html#bpy.types.ToolSettings.use_gpencil_weight_data_add) - [use_gpu_subdivision (bpy.types.PreferencesSystem attribute)](bpy.types.PreferencesSystem.html#bpy.types.PreferencesSystem.use_gpu_subdivision) - [use_grab_active_vertex (bpy.types.Brush attribute)](bpy.types.Brush.html#bpy.types.Brush.use_grab_active_vertex) - [use_grab_cursor (bpy.types.Gizmo attribute)](bpy.types.Gizmo.html#bpy.types.Gizmo.use_grab_cursor) - [use_grab_silhouette (bpy.types.Brush attribute)](bpy.types.Brush.html#bpy.types.Brush.use_grab_silhouette) - [use_gravity (bpy.types.Scene attribute)](bpy.types.Scene.html#bpy.types.Scene.use_gravity)   - [(bpy.types.WalkNavigation attribute)](bpy.types.WalkNavigation.html#bpy.types.WalkNavigation.use_gravity) - [use_gravity_falloff (bpy.types.FieldSettings attribute)](bpy.types.FieldSettings.html#bpy.types.FieldSettings.use_gravity_falloff) - [use_grayscale_preview (bpy.types.MovieTrackingTrack attribute)](bpy.types.MovieTrackingTrack.html#bpy.types.MovieTrackingTrack.use_grayscale_preview)   - [(bpy.types.SpaceClipEditor attribute)](bpy.types.SpaceClipEditor.html#bpy.types.SpaceClipEditor.use_grayscale_preview) - [use_grease_pencil (bpy.types.ViewLayer attribute)](bpy.types.ViewLayer.html#bpy.types.ViewLayer.use_grease_pencil) - [use_grease_pencil_lights (bpy.types.Object attribute)](bpy.types.Object.html#bpy.types.Object.use_grease_pencil_lights) - [use_grease_pencil_multi_frame_editing (bpy.types.ToolSettings attribute)](bpy.types.ToolSettings.html#bpy.types.ToolSettings.use_grease_pencil_multi_frame_editing) - [use_green_channel (bpy.types.MovieTrackingTrack attribute)](bpy.types.MovieTrackingTrack.html#bpy.types.MovieTrackingTrack.use_green_channel) - [use_group_restrict (bpy.types.VertexPaint attribute)](bpy.types.VertexPaint.html#bpy.types.VertexPaint.use_group_restrict) - [use_guide (bpy.types.FluidDomainSettings attribute)](bpy.types.FluidDomainSettings.html#bpy.types.FluidDomainSettings.use_guide)   - [(bpy.types.GPencilSculptGuide attribute)](bpy.types.GPencilSculptGuide.html#bpy.types.GPencilSculptGuide.use_guide) - [use_guide_path_add (bpy.types.FieldSettings attribute)](bpy.types.FieldSettings.html#bpy.types.FieldSettings.use_guide_path_add) - [use_guide_path_weight (bpy.types.FieldSettings attribute)](bpy.types.FieldSettings.html#bpy.types.FieldSettings.use_guide_path_weight) - [use_hair_bspline (bpy.types.ParticleSettings attribute)](bpy.types.ParticleSettings.html#bpy.types.ParticleSettings.use_hair_bspline) - [use_hair_dynamics (bpy.types.ParticleSystem attribute)](bpy.types.ParticleSystem.html#bpy.types.ParticleSystem.use_hair_dynamics) - [use_half_precision (bpy.types.Image attribute)](bpy.types.Image.html#bpy.types.Image.use_half_precision) - [use_hardness_pressure (bpy.types.Brush attribute)](bpy.types.Brush.html#bpy.types.Brush.use_hardness_pressure) - [use_high_quality_normals (bpy.types.RenderSettings attribute)](bpy.types.RenderSettings.html#bpy.types.RenderSettings.use_high_quality_normals) - [use_highlight_tiles (bpy.types.RenderEngine attribute)](bpy.types.RenderEngine.html#bpy.types.RenderEngine.use_highlight_tiles) - [use_hole_tolerant (bpy.types.BooleanModifier attribute)](bpy.types.BooleanModifier.html#bpy.types.BooleanModifier.use_hole_tolerant) - [use_ik_limit_x (bpy.types.PoseBone attribute)](bpy.types.PoseBone.html#bpy.types.PoseBone.use_ik_limit_x) - [use_ik_limit_y (bpy.types.PoseBone attribute)](bpy.types.PoseBone.html#bpy.types.PoseBone.use_ik_limit_y) - [use_ik_limit_z (bpy.types.PoseBone attribute)](bpy.types.PoseBone.html#bpy.types.PoseBone.use_ik_limit_z) - [use_ik_linear_control (bpy.types.PoseBone attribute)](bpy.types.PoseBone.html#bpy.types.PoseBone.use_ik_linear_control) - [use_ik_rotation_control (bpy.types.PoseBone attribute)](bpy.types.PoseBone.html#bpy.types.PoseBone.use_ik_rotation_control) - [use_image_boundary_trimming (bpy.types.GreasePencilLineartModifier attribute)](bpy.types.GreasePencilLineartModifier.html#bpy.types.GreasePencilLineartModifier.use_image_boundary_trimming) - [use_image_pin (bpy.types.SpaceImageEditor attribute)](bpy.types.SpaceImageEditor.html#bpy.types.SpaceImageEditor.use_image_pin) - [use_in_air (bpy.types.BoidRule attribute)](bpy.types.BoidRule.html#bpy.types.BoidRule.use_in_air) - [use_incremental_displace (bpy.types.DynamicPaintSurface attribute)](bpy.types.DynamicPaintSurface.html#bpy.types.DynamicPaintSurface.use_incremental_displace) - [use_inflow (bpy.types.FluidFlowSettings attribute)](bpy.types.FluidFlowSettings.html#bpy.types.FluidFlowSettings.use_inflow) - [use_influence (bpy.types.FModifier attribute)](bpy.types.FModifier.html#bpy.types.FModifier.use_influence) - [use_inherit_rotation (bpy.types.Bone attribute)](bpy.types.Bone.html#bpy.types.Bone.use_inherit_rotation)   - [(bpy.types.EditBone attribute)](bpy.types.EditBone.html#bpy.types.EditBone.use_inherit_rotation) - [use_initial_rest_length (bpy.types.SPHFluidSettings attribute)](bpy.types.SPHFluidSettings.html#bpy.types.SPHFluidSettings.use_initial_rest_length) - [use_initial_velocity (bpy.types.FluidFlowSettings attribute)](bpy.types.FluidFlowSettings.html#bpy.types.FluidFlowSettings.use_initial_velocity) - [use_insertkey_needed (bpy.types.KeyingSet attribute)](bpy.types.KeyingSet.html#bpy.types.KeyingSet.use_insertkey_needed)   - [(bpy.types.KeyingSetPath attribute)](bpy.types.KeyingSetPath.html#bpy.types.KeyingSetPath.use_insertkey_needed) - [use_insertkey_override_needed (bpy.types.KeyingSet attribute)](bpy.types.KeyingSet.html#bpy.types.KeyingSet.use_insertkey_override_needed)   - [(bpy.types.KeyingSetPath attribute)](bpy.types.KeyingSetPath.html#bpy.types.KeyingSetPath.use_insertkey_override_needed) - [use_insertkey_override_visual (bpy.types.KeyingSet attribute)](bpy.types.KeyingSet.html#bpy.types.KeyingSet.use_insertkey_override_visual)   - [(bpy.types.KeyingSetPath attribute)](bpy.types.KeyingSetPath.html#bpy.types.KeyingSetPath.use_insertkey_override_visual) - [use_insertkey_visual (bpy.types.KeyingSet attribute)](bpy.types.KeyingSet.html#bpy.types.KeyingSet.use_insertkey_visual)   - [(bpy.types.KeyingSetPath attribute)](bpy.types.KeyingSetPath.html#bpy.types.KeyingSetPath.use_insertkey_visual) - [use_insertkey_xyz_to_rgb (bpy.types.PreferencesEdit attribute)](bpy.types.PreferencesEdit.html#bpy.types.PreferencesEdit.use_insertkey_xyz_to_rgb) - [use_instance_faces_scale (bpy.types.Object attribute)](bpy.types.Object.html#bpy.types.Object.use_instance_faces_scale) - [use_instance_vertices_rotation (bpy.types.Object attribute)](bpy.types.Object.html#bpy.types.Object.use_instance_vertices_rotation) - [use_interlace_swap (bpy.types.Stereo3dDisplay attribute)](bpy.types.Stereo3dDisplay.html#bpy.types.Stereo3dDisplay.use_interlace_swap)   - [(bpy.types.Stereo3dFormat attribute)](bpy.types.Stereo3dFormat.html#bpy.types.Stereo3dFormat.use_interlace_swap) - [use_internal_springs (bpy.types.ClothSettings attribute)](bpy.types.ClothSettings.html#bpy.types.ClothSettings.use_internal_springs) - [use_interpolation (bpy.types.ImageTexture attribute)](bpy.types.ImageTexture.html#bpy.types.ImageTexture.use_interpolation) - [use_intersection (bpy.types.GreasePencilLineartModifier attribute)](bpy.types.GreasePencilLineartModifier.html#bpy.types.GreasePencilLineartModifier.use_intersection) - [use_intersection_mask (bpy.types.GreasePencilLineartModifier attribute)](bpy.types.GreasePencilLineartModifier.html#bpy.types.GreasePencilLineartModifier.use_intersection_mask) - [use_intersection_match (bpy.types.GreasePencilLineartModifier attribute)](bpy.types.GreasePencilLineartModifier.html#bpy.types.GreasePencilLineartModifier.use_intersection_match) - [use_intersection_priority_override (bpy.types.MaterialLineArt attribute)](bpy.types.MaterialLineArt.html#bpy.types.MaterialLineArt.use_intersection_priority_override)   - [(bpy.types.ObjectLineArt attribute)](bpy.types.ObjectLineArt.html#bpy.types.ObjectLineArt.use_intersection_priority_override) - [use_inverse_smooth_pressure (bpy.types.Brush attribute)](bpy.types.Brush.html#bpy.types.Brush.use_inverse_smooth_pressure) - [use_invert_collection (bpy.types.GreasePencilLineartModifier attribute)](bpy.types.GreasePencilLineartModifier.html#bpy.types.GreasePencilLineartModifier.use_invert_collection) - [use_invert_cull (bpy.types.GreasePencilShrinkwrapModifier attribute)](bpy.types.GreasePencilShrinkwrapModifier.html#bpy.types.GreasePencilShrinkwrapModifier.use_invert_cull)   - [(bpy.types.ShrinkwrapConstraint attribute)](bpy.types.ShrinkwrapConstraint.html#bpy.types.ShrinkwrapConstraint.use_invert_cull)   - [(bpy.types.ShrinkwrapModifier attribute)](bpy.types.ShrinkwrapModifier.html#bpy.types.ShrinkwrapModifier.use_invert_cull) - [use_invert_output (bpy.types.GreasePencilWeightAngleModifier attribute)](bpy.types.GreasePencilWeightAngleModifier.html#bpy.types.GreasePencilWeightAngleModifier.use_invert_output)   - [(bpy.types.GreasePencilWeightProximityModifier attribute)](bpy.types.GreasePencilWeightProximityModifier.html#bpy.types.GreasePencilWeightProximityModifier.use_invert_output) - [use_invert_silhouette (bpy.types.GreasePencilLineartModifier attribute)](bpy.types.GreasePencilLineartModifier.html#bpy.types.GreasePencilLineartModifier.use_invert_silhouette) - [use_invert_sort (bpy.types.MovieTrackingDopesheet attribute)](bpy.types.MovieTrackingDopesheet.html#bpy.types.MovieTrackingDopesheet.use_invert_sort) - [use_italic (bpy.types.TextCharacterFormat attribute)](bpy.types.TextCharacterFormat.html#bpy.types.TextCharacterFormat.use_italic)   - [(bpy.types.TextStrip attribute)](bpy.types.TextStrip.html#bpy.types.TextStrip.use_italic) - [use_jitter_pressure (bpy.types.BrushGpencilSettings attribute)](bpy.types.BrushGpencilSettings.html#bpy.types.BrushGpencilSettings.use_jitter_pressure) - [use_jpeg2k_cinema_48 (bpy.types.ImageFormatSettings attribute)](bpy.types.ImageFormatSettings.html#bpy.types.ImageFormatSettings.use_jpeg2k_cinema_48) - [use_jpeg2k_cinema_preset (bpy.types.ImageFormatSettings attribute)](bpy.types.ImageFormatSettings.html#bpy.types.ImageFormatSettings.use_jpeg2k_cinema_preset) - [use_jpeg2k_ycc (bpy.types.ImageFormatSettings attribute)](bpy.types.ImageFormatSettings.html#bpy.types.ImageFormatSettings.use_jpeg2k_ycc) - [use_keep_caps_eraser (bpy.types.BrushGpencilSettings attribute)](bpy.types.BrushGpencilSettings.html#bpy.types.BrushGpencilSettings.use_keep_caps_eraser) - [use_keep_loop (bpy.types.GreasePencilTimeModifier attribute)](bpy.types.GreasePencilTimeModifier.html#bpy.types.GreasePencilTimeModifier.use_keep_loop) - [use_keep_shape (bpy.types.GreasePencilOutlineModifier attribute)](bpy.types.GreasePencilOutlineModifier.html#bpy.types.GreasePencilOutlineModifier.use_keep_shape)   - [(bpy.types.GreasePencilSmoothModifier attribute)](bpy.types.GreasePencilSmoothModifier.html#bpy.types.GreasePencilSmoothModifier.use_keep_shape) - [use_keyed_timing (bpy.types.ParticleSystem attribute)](bpy.types.ParticleSystem.html#bpy.types.ParticleSystem.use_keyed_timing) - [use_keyframe_cycle_aware (bpy.types.ToolSettings attribute)](bpy.types.ToolSettings.html#bpy.types.ToolSettings.use_keyframe_cycle_aware) - [use_keyframe_insert_auto (bpy.types.ToolSettings attribute)](bpy.types.ToolSettings.html#bpy.types.ToolSettings.use_keyframe_insert_auto) - [use_keyframe_insert_available (bpy.types.PreferencesEdit attribute)](bpy.types.PreferencesEdit.html#bpy.types.PreferencesEdit.use_keyframe_insert_available) - [use_keyframe_insert_keyingset (bpy.types.ToolSettings attribute)](bpy.types.ToolSettings.html#bpy.types.ToolSettings.use_keyframe_insert_keyingset) - [use_keyframe_insert_needed (bpy.types.PreferencesEdit attribute)](bpy.types.PreferencesEdit.html#bpy.types.PreferencesEdit.use_keyframe_insert_needed) - [use_keyframe_selection (bpy.types.MovieTrackingSettings attribute)](bpy.types.MovieTrackingSettings.html#bpy.types.MovieTrackingSettings.use_keyframe_selection) - [use_land (bpy.types.BoidSettings attribute)](bpy.types.BoidSettings.html#bpy.types.BoidSettings.use_land) - [use_layer_group_filter (bpy.types.GreasePencilArrayModifier attribute)](bpy.types.GreasePencilArrayModifier.html#bpy.types.GreasePencilArrayModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilBuildModifier attribute)](bpy.types.GreasePencilBuildModifier.html#bpy.types.GreasePencilBuildModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilColorModifier attribute)](bpy.types.GreasePencilColorModifier.html#bpy.types.GreasePencilColorModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilDashModifierData attribute)](bpy.types.GreasePencilDashModifierData.html#bpy.types.GreasePencilDashModifierData.use_layer_group_filter)   - [(bpy.types.GreasePencilEnvelopeModifier attribute)](bpy.types.GreasePencilEnvelopeModifier.html#bpy.types.GreasePencilEnvelopeModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilHookModifier attribute)](bpy.types.GreasePencilHookModifier.html#bpy.types.GreasePencilHookModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilLatticeModifier attribute)](bpy.types.GreasePencilLatticeModifier.html#bpy.types.GreasePencilLatticeModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilLengthModifier attribute)](bpy.types.GreasePencilLengthModifier.html#bpy.types.GreasePencilLengthModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilMirrorModifier attribute)](bpy.types.GreasePencilMirrorModifier.html#bpy.types.GreasePencilMirrorModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilMultiplyModifier attribute)](bpy.types.GreasePencilMultiplyModifier.html#bpy.types.GreasePencilMultiplyModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilNoiseModifier attribute)](bpy.types.GreasePencilNoiseModifier.html#bpy.types.GreasePencilNoiseModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilOffsetModifier attribute)](bpy.types.GreasePencilOffsetModifier.html#bpy.types.GreasePencilOffsetModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilOpacityModifier attribute)](bpy.types.GreasePencilOpacityModifier.html#bpy.types.GreasePencilOpacityModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilOutlineModifier attribute)](bpy.types.GreasePencilOutlineModifier.html#bpy.types.GreasePencilOutlineModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilShrinkwrapModifier attribute)](bpy.types.GreasePencilShrinkwrapModifier.html#bpy.types.GreasePencilShrinkwrapModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilSimplifyModifier attribute)](bpy.types.GreasePencilSimplifyModifier.html#bpy.types.GreasePencilSimplifyModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilSmoothModifier attribute)](bpy.types.GreasePencilSmoothModifier.html#bpy.types.GreasePencilSmoothModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilSubdivModifier attribute)](bpy.types.GreasePencilSubdivModifier.html#bpy.types.GreasePencilSubdivModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilTextureModifier attribute)](bpy.types.GreasePencilTextureModifier.html#bpy.types.GreasePencilTextureModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilThickModifierData attribute)](bpy.types.GreasePencilThickModifierData.html#bpy.types.GreasePencilThickModifierData.use_layer_group_filter)   - [(bpy.types.GreasePencilTimeModifier attribute)](bpy.types.GreasePencilTimeModifier.html#bpy.types.GreasePencilTimeModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilTintModifier attribute)](bpy.types.GreasePencilTintModifier.html#bpy.types.GreasePencilTintModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilWeightAngleModifier attribute)](bpy.types.GreasePencilWeightAngleModifier.html#bpy.types.GreasePencilWeightAngleModifier.use_layer_group_filter)   - [(bpy.types.GreasePencilWeightProximityModifier attribute)](bpy.types.GreasePencilWeightProximityModifier.html#bpy.types.GreasePencilWeightProximityModifier.use_layer_group_filter) - [use_layer_pass_filter (bpy.types.GreasePencilArrayModifier attribute)](bpy.types.GreasePencilArrayModifier.html#bpy.types.GreasePencilArrayModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilBuildModifier attribute)](bpy.types.GreasePencilBuildModifier.html#bpy.types.GreasePencilBuildModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilColorModifier attribute)](bpy.types.GreasePencilColorModifier.html#bpy.types.GreasePencilColorModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilDashModifierData attribute)](bpy.types.GreasePencilDashModifierData.html#bpy.types.GreasePencilDashModifierData.use_layer_pass_filter)   - [(bpy.types.GreasePencilEnvelopeModifier attribute)](bpy.types.GreasePencilEnvelopeModifier.html#bpy.types.GreasePencilEnvelopeModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilHookModifier attribute)](bpy.types.GreasePencilHookModifier.html#bpy.types.GreasePencilHookModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilLatticeModifier attribute)](bpy.types.GreasePencilLatticeModifier.html#bpy.types.GreasePencilLatticeModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilLengthModifier attribute)](bpy.types.GreasePencilLengthModifier.html#bpy.types.GreasePencilLengthModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilMirrorModifier attribute)](bpy.types.GreasePencilMirrorModifier.html#bpy.types.GreasePencilMirrorModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilMultiplyModifier attribute)](bpy.types.GreasePencilMultiplyModifier.html#bpy.types.GreasePencilMultiplyModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilNoiseModifier attribute)](bpy.types.GreasePencilNoiseModifier.html#bpy.types.GreasePencilNoiseModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilOffsetModifier attribute)](bpy.types.GreasePencilOffsetModifier.html#bpy.types.GreasePencilOffsetModifier.use_layer_pass_filter)   - [(bpy.types.GreasePencilOpacityModifier attribute)](bpy.ty