'Replaces variables from a scalar item.
If the item is not a string it is returned as is. If it is a ${scalar}
variable its value is returned. Otherwise variables are replaced with
\'replace_string\'. Result may be any object.'

def replace_scalar(self, item, ignore_errors=False):

    if self._cannot_have_variables(item):
        return unescape(item)
    return self._replace_scalar(item, ignore_errors=ignore_errors)
