docs: def min_base_quality(self):
          '''
          The minimum of the base qualities. In the case of a deletion, in which
          case there are no bases in this PileupElement, the minimum is taken
          over the sequenced bases immediately before and after the deletion.
          '''
          try:
              return min(self.base_qualities)
          except ValueError:
              # We are mid-deletion. We return the minimum of the adjacent bases.
              assert self.offset_start == self.offset_end
              adjacent_qualities = [
                  self.alignment.query_qualities[offset]
                  for offset in [self.offset_start - 1, self.offset_start]
                  if 0 <= offset < len(self.alignment.query_qualities)
              ]
              return min(adjacent_qualities)