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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 get_leaf_output(self, tree_id, leaf_id):
 """Get the output of a leaf. Parameters tree_id : int The index of the tree. leaf_id : int The index of the leaf in the tree. Returns ------- result : float The output of the leaf. """

        ret = ctypes.c_double(0)
        _safe_call(_LIB.LGBM_BoosterGetLeafValue(
            self.handle,
            ctypes.c_int(tree_id),
            ctypes.c_int(leaf_id),
            ctypes.byref(ret)))
        return ret.value