This will do what you want: Applies modifiers for all selected objects:
import bpy
import bmesh
for ob in [ob for ob in bpy.context.selected_objects if ob.type == 'MESH']:
b_me = bmesh.new()
b_me.from_object(ob, bpy.context.scene)
b_me.to_mesh(ob.data)
b_me.free()
for mod in ob.modifiers:
ob.modifiers.remove(mod)