<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _coerce_method(converter):
 """ Install the scalar coercion methods. """


    def wrapper(self):
        if len(self) == 1:
            return converter(self.iloc[0])
        raise TypeError("cannot convert the series to "
                        "{0}".format(str(converter)))

    wrapper.__name__ = "__{name}__".format(name=converter.__name__)
    return wrapper