| import bpy
from mathutils import *
import math
def apply_matrix(mat, objs):
    for i in range(len(objs)):
        obj = objs[i]
        print (obj.matrix_world)
        print(mat)
        obj.matrix_world = mat*obj.matrix_world
mat = Euler([0,0,30*math.pi/180], 'XYZ').to_matrix().to_4x4()
apply_matrix(mat, [ o for o in bpy.context.scene.objects if o.select])
 | 
Blender python API quick-start
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