private static @NotNull PsiElement addFieldToSetUp(PyClass clazz, Function<String, PyStatement> callback) {
    final PyFunction init = clazz.findMethodByName(PyNames.TESTCASE_SETUP_NAME, false, null);
    if (init != null) {
      return AddFieldQuickFix.appendToMethod(init, callback);
    }
    final PyFunctionBuilder builder = new PyFunctionBuilder(PyNames.TESTCASE_SETUP_NAME, clazz);
    builder.parameter(PyNames.CANONICAL_SELF);
    PyFunction setUp = builder.buildFunction();
    final PyStatementList statements = clazz.getStatementList();
    final PsiElement anchor = statements.getFirstChild();
    setUp = (PyFunction)statements.addBefore(setUp, anchor);
    return AddFieldQuickFix.appendToMethod(setUp, callback);
  }
private static @NotNull PsiElement addFieldToSetUp(PyClass clazz, Function<String, PyStatement> callback)