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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 _load_nucmer_hits(self, infile):
        '''Returns dict ref name => list of nucmer hits from infile'''
        hits = {}
        file_reader = pymummer.coords_file.reader(infile)
        for al in file_reader:
            if al.ref_name not in hits:
                hits[al.ref_name] = []
            hits[al.ref_name].append(al)
        return hits