code: def generatePreKeys(start, count):
          
          results = []
          start -= 1
          for i in range(0, count):
              preKeyId = ((start + i) % (Medium.MAX_VALUE - 1)) + 1
              results.append(PreKeyRecord(preKeyId, Curve.generateKeyPair()))
  
          return results
docs: Generate a list of PreKeys.  Clients should do this at install time, and
          subsequently any time the list of PreKeys stored on the server runs low.
  
          PreKey IDs are shorts, so they will eventually be repeated.  Clients should
          store PreKeys in a circular buffer, so that they are repeated as infrequently
          as possible.
  
          @param start The starting PreKey ID, inclusive.
          @param count The number of PreKeys to generate.
          @return the list of generated PreKeyRecords.