code: def lookup_statistic(score, stats):
      
      if score in stats:
          return stats[score]['q'], stats[score]['PEP'], None
      else:
          lower, warning = None, None
          for stat_score in sorted(stats.keys()):
              if score < stat_score:
                  break
              lower = stat_score
          if score > stat_score:
              warning = ('WARNING! Values found with higher svm_score than in '
                         'qvality recalculation!')
          if not lower:
              warning = ('WARNING! Values found with lower svm_score than in '
                         'qvality recalculation were set to PEP=1, qval=1.')
              return '1', '1', warning
          qval = (float(stats[stat_score]['q']) + float(stats[lower]['q'])) / 2
          pep = (float(stats[stat_score]['PEP']) +
                 float(stats[lower]['PEP'])) / 2
      return str(qval), str(pep), warning
docs: Finds statistics that correspond to PSM/peptide/protein feature's
      score. Loops through list of qvality generated scores until it finds
      values closest to the feature's svm_score.