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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 _cmp_fstruct(self, s1, s2, frac_tol, mask):
 """ Returns true if a matching exists between s2 and s2 under frac_tol. s2 should be a subset of s1 """

        if len(s2) > len(s1):
            raise ValueError("s1 must be larger than s2")
        if mask.shape != (len(s2), len(s1)):
            raise ValueError("mask has incorrect shape")

        return is_coord_subset_pbc(s2, s1, frac_tol, mask)