I have defined a Button with Tklinter

```
class ventanapp(Tk):

    def initialize(self):
        self.grid()
        self.entry = Entry(self)
        msg = Message(text=' SSH - Ingresar IP ->')
        self.entry.grid(column=0,row=0,sticky='EW')
        button = Button(self,text=u"realizar la conexion",command=ssh.crear_ssh())
        button.grid(column=1,row=0)

```

But when i call the `command=ssh.crear_ssh()` from Another Class

```
class ssh():
    def crear_ssh():
        print('PONER ACA EL CODIGO DE LA CONEXION')`

```

I receive the error : "global name 'ssh' is not defined"

Any ideas? Thanks!