def convert_value(self, value):
if isinstance(value, str):<EOL><INDENT>assert value.startswith(self.symbol), "<STR_LIT>" + self.symbol<EOL>value = value.lstrip(self.symbol)<EOL><DEDENT>return super().convert_value(value)<EOL>
Convert value to float. If value is a string, ensure that the first
        character is the same as symbol ie. the value is in the currency this
        formatter is representing.