docs: def getScan(self, specId, peptide=None):
          """
          get a random scan
          """
          sql = self.base_sql + " where sh.SpectrumID = %d and p.Sequence = '%s'"%(int(specId),peptide)
          self.cur.execute(sql)
          i = self.cur.fetchone()
          if not i:
              return None
          scan = self.parseFullScan(i)
          scan.spectrumId = specId
          return scan