'After stripping entered name, check that it is a  sensible
ConfigParser file section name. Return it if it is, \'\' if not.'

def name_ok(self):

    name = self.name.get().strip()
    if (not name):
        tkMessageBox.showerror(title='Name    Error', message='No    name    specified.', parent=self)
    elif (len(name) > 30):
        tkMessageBox.showerror(title='Name    Error', message=('Name    too    long.    It    should    be    no    more    than    ' + '30    characters.'), parent=self)
        name = ''
    elif (name in self.used_names):
        tkMessageBox.showerror(title='Name    Error', message='This    name    is    already    in    use.', parent=self)
        name = ''
    return name
