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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 coverage(self):
 """ Returns NumPy array indicating number of reads covering each nucleotides of this sequence. """

        variant_start_index, variant_end_index = self.variant_indices()
        n_nucleotides = len(self)
        coverage_array = np.zeros(n_nucleotides, dtype="int32")
        for read in self.reads:
            coverage_array[
                max(0, variant_start_index - len(read.prefix)):
                min(n_nucleotides, variant_end_index + len(read.suffix))] += 1
        return coverage_array