Module(body=[Assign(targets=[Name(id='var1',
                                  ctx=Store())],
                    value=Str(s='foo')),
             If(test=Call(func=Name(id='isinstance',
                                    ctx=Load()),
                          args=[Name(id='var1',
                                     ctx=Load()),
                                Name(id='str',
                                     ctx=Load())],
                          keywords=[],
                          starargs=None,
                          kwargs=None),
                body=[Print(dest=None,
                            values=[Str(s='var1 is a string')],
                            nl=True)],
                orelse=[])])