def _fitch_intersect(self, arrays):
        """
        Find the intersection of any number of 1D arrays.
        Return the sorted, unique values that are in all of the input arrays.
        Adapted from numpy.lib.arraysetops.intersect1d
        """
        def pairwise_intersect(arr1, arr2):
            s2 = set(arr2)
            b3 = [val for val in arr1 if val in s2]
            return b3

        arrays = list(arrays) # allow assignment
        N = len(arrays)
        while N > 1:
            arr1 = arrays.pop()
            arr2 = arrays.pop()
            arr = pairwise_intersect(arr1, arr2)
            arrays.append(arr)
            N = len(arrays)

        return arrays[0]
Find the intersection of any number of 1D arrays.
        Return the sorted, unique values that are in all of the input arrays.
        Adapted from numpy.lib.arraysetops.intersect1d