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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 addPos(self, dp_x=None, dy=None, dz=None):
 """Add vector to current actor position."""

        p = np.array(self.GetPosition())
        if dz is None:  # assume dp_x is of the form (x,y,z)
            self.SetPosition(p + dp_x)
        else:
            self.SetPosition(p + [dp_x, dy, dz])
        if self.trail:
            self.updateTrail()
        return self