<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def var(self, bias=False, *args, **kwargs):
 """ Exponential weighted moving variance. """

        nv.validate_window_func('var', args, kwargs)

        def f(arg):
            return libwindow.ewmcov(arg, arg, self.com, int(self.adjust),
                                    int(self.ignore_na), int(self.min_periods),
                                    int(bias))

        return self._apply(f, **kwargs)