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from pprint import pprint
import bpy
import bmesh

# get the active object

for obj in bpy.data.objects:

    if obj.type == 'MESH':
        me = obj.data

        if me.is_editmode:
            current_selection = [i.index for i in bmesh.from_edit_mesh(bpy.context.active_object.data).faces if i.select]
            bpy.ops.mesh.select_more()

            new_selection = [i.index for i in bmesh.from_edit_mesh(bpy.context.active_object.data).faces if i.select]
            deselect = []

            for face in new_selection:
                if face in current_selection:
                    deselect.append(face)

            # deselect
            for face in deselect:
                test = bmesh.from_edit_mesh(bpy.context.active_object.data)
                test.faces[face].select_set(False)