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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 s_demand(self, bus):
 """ Returns the total complex power demand. """

        Svl = array([complex(g.p, g.q) for g in self.generators if
                    (g.bus == bus) and g.is_load], dtype=complex64)

        Sd = complex(bus.p_demand, bus.q_demand)

        return -sum(Svl) + Sd