code: @Pure
    protected final @Nullable Attribute get_stack_map_table_attribute(MethodGen mgen) {
      for (Attribute a : mgen.getCodeAttributes()) {
        if (is_stack_map_table(a)) {
          return a;
        }
      }
      return null;
    }
docs: Find the StackMapTable attribute for a method. Return null if there isn't one.
  
  @param mgen the method
  @return the StackMapTable attribute for the method (or null if not present)