docs: def allele_summary(self, locus, score=lambda x: x.num_reads()):
          '''
          Convenience method to summarize the evidence for each of the alleles
          present at a locus. Applies a score function to the PileupCollection
          associated with each allele.
  
          See also `PileupCollection.group_by_allele`.
  
          Parameters
          ----------
          locus : Locus
              The reference locus, encompassing 0 or more bases.
  
          score (optional) : PileupCollection -> object
              Function to apply to summarize the evidence for each allele.
              Default: count number of reads.
  
          Returns
          ----------
          List of (allele, score) pairs.
          '''
          locus = to_locus(locus)
          return [
              (allele, score(x))
              for (allele, x) in self.group_by_allele(locus).items()
          ]