function digStateInClassBody(obj) {
  if (obj.type !== 'ClassBody')
    return;
  let ret = [];
  obj.body.forEach((elem) => {
    if (elem.type = "MethodDefinition" && elem.key.name === "constructor") {
      ret = digStateInBlockStatement(elem.value.body);
    }
  });
  return ret;
}
traverses through AST object and returns entry point for constructor Object;
@param {Object} obj - classBody object from AST