'Override this method if you want to customize data inputs or
validation exceptions.'

def get_input_data(self, field, message, default=None):

    raw_value = input(message)
    if (default and (raw_value == '')):
        raw_value = default
    try:
        val = field.clean(raw_value, None)
    except exceptions.ValidationError as e:
        self.stderr.write(('Error:    %s' % ';    '.join(e.messages)))
        val = None
    return val
