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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 type(self):
 """The type of the functional."""

        if self.xc in self.defined_aliases: return self.defined_aliases[self.xc].type
        xc = (self.x, self.c)
        if xc in self.defined_aliases: return self.defined_aliases[xc].type

        # If self is not in defined_aliases, use LibxcFunc family
        if self.xc is not None: return self.xc.family
        return "+".join([self.x.family, self.c.family])