How to add a new UV map to all selected objects?

Question

I would like to select multiple objects and add a custom UV set to all of them. My version works for one selected object only but not for multiple selected objects.

import bpy

# Get all selected objects
selected_objects = bpy.context.selected_objects 

for obj in selected_objects:
    # Add new UV set
    bpy.ops.mesh.uv_texture_add() 
    # Set new UV set name for active UV set
    bpy.context.object.data.uv_layers.active.name = "UV_ao"

What's wrong with my code?

Answer 1

You can get rid of the uv_texture_add() operator by adding a new UVLoopLayer:

import bpy

for obj in bpy.context.selected_objects:
    # Make sure this is a mesh object and that it doesn't already use this UV Map
    if obj.type == 'MESH' and "UV_ao" not in obj.data.uv_layers:
        obj.data.uv_layers.new(name="UV_ao")

Answer 2

In order to make the operator work for multiple objects, the current object in the loop needs to be assigned to ViewLayer.active before calling uv_texture_add():

import bpy

# Do the following for all selected objects
for obj in bpy.context.selected_objects: 
    # Set current object in the selection as active
    bpy.context.view_layer.objects.active = obj 
    # Add new UV set to active object
    bpy.ops.mesh.uv_texture_add() 
    # Set the name of the uv layer
    obj.data.uv_layers.active.name = "UV_ao"

Related: Blender 2.8 API, python, set active object

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Another way is overriding the context of the operator by passing the object:

import bpy

# Do the following for all selected objects
for obj in bpy.context.selected_objects:
    # Override the context by passing the current object
    bpy.ops.mesh.uv_texture_add({'object': obj})
    # Set the name of the uv layer
    obj.data.uv_layers.active.name = "UV_ao"