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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_idxs(exprs):
 """ Finds sympy.tensor.indexed.Idx instances and returns them. """

    idxs = set()
    for expr in (exprs):
        for i in expr.find(sympy.Idx):
            idxs.add(i)
    return sorted(idxs, key=str)