if the following are true:

• the line at time t = i
• the tab at time t = j
• statement at line i, tab j = assign statement with target x and expression (obj_name.method_name(args))
• expression state at time t = "end_expr"

then Variables Map at time (t + 1) = result of storing (Return Value at time t) at key: x in map: (Variables Map at time t)