<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def distinct(self):
 """Return sets of indices for each distinct haplotype."""


        # setup collection
        d = collections.defaultdict(set)

        # iterate over haplotypes
        for i in range(self.shape[1]):

            # hash the haplotype
            k = hash(self.values[:, i].tobytes())

            # collect
            d[k].add(i)

        # extract sets, sorted by most common
        return sorted(d.values(), key=len, reverse=True)