void () { final Module module = myFixture.getModule(); checkRequirements(PyPackageUtil.getRequirementsFromTxt(module), 1); WriteCommandAction.runWriteCommandAction(myFixture.getProject(), () -> PyPackageUtil.addRequirementToTxtOrSetupPy(module, "Markdown", LanguageLevel.PYTHON34)); checkRequirements(PyPackageUtil.getRequirementsFromTxt(module)); }