def drop_missing(self):
        r"""Delete missing value.

        Returns:
            Result

        """
        newvalues = []
        newdescs = []
        for d, v in self.items():
            if not is_missing(v):
                newvalues.append(v)
                newdescs.append(d)

        return self.__class__(self.mol, newvalues, newdescs)
r"""Delete missing value.

        Returns:
            Result