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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 _make_expr_ops(self, op_list, op_dict=None, op_class=None):
 """ Fill up `self._op_expr` dict. :param op_list: A list of operation names. :param op_dict: A dictionary of operation methods. :param op_class: Where the operation method comes from. :return: """

        for o in op_list:
            if op_dict is not None:
                if o in op_dict:
                    self._op_expr[o] = op_dict[o]
                else:
                    l.warning("Operation %s not in op_dict.", o)
            else:
                if hasattr(op_class, o):
                    self._op_expr[o] = getattr(op_class, o)
                else:
                    l.warning("Operation %s not in op_class %s.", o, op_class)