• expression state at time t = "call_function_begin"
• the expression at time t = obj_name.method_name(args)
• value at obj_name in map (Variables Map at time t) = Python reference index
• the element at index index of stack (Python Object Store at time t) = Python object: [ entry "__class_name__": class_name, e_rest ]
• map (Class Map at time t) contains key class_name = True

then expression state at time (t + 1) = "call_build_args"