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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 group_by(self, by=None, **additional_grouping_expressions):
 """ Create an intermediate grouped table expression, pending some group operation to be applied with it. Examples -------- Notes ----- group_by and groupby are equivalent, with `groupby` being provided for ease-of-use for pandas users. Returns ------- grouped_expr : GroupedTableExpr """

        from ibis.expr.groupby import GroupedTableExpr

        return GroupedTableExpr(self, by, **additional_grouping_expressions)