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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def filter(self, func, dropna=True, *args, **kwargs):
 # noqa """ Return a copy of a Series excluding elements from groups that do not satisfy the boolean criterion specified by func. Parameters func : function To apply to each group. Should return True or False. dropna : Drop groups that do not pass the filter. True by default; if False, groups that evaluate False are filled with NaNs. Examples -------- 1 2 3 4 5 6 Name: B, dtype: int64 Returns ------- filtered : Series """

        if isinstance(func, str):
            wrapper = lambda x: getattr(x, func)(*args, **kwargs)
        else:
            wrapper = lambda x: func(x, *args, **kwargs)

        # Interpret np.nan as False.
        def true_and_notna(x, *args, **kwargs):
            b = wrapper(x, *args, **kwargs)
            return b and notna(b)

        try:
            indices = [self._get_index(name) for name, group in self
                       if true_and_notna(group)]
        except ValueError:
            raise TypeError("the filter must return a boolean result")
        except TypeError:
            raise TypeError("the filter must return a boolean result")

        filtered = self._apply_filter(indices, dropna)
        return filtered