simplest python k-way merging sort

sort.py

import heapq
import random
import threading

#k thrads
k=4

#Generate n numbers for each thread to process.
n=10

def GenerateNumbers(a,b):
  numbers=[]
  for i in xrange(n):
    numbers.append(random.randint(a,b))
  return numbers

class SortingThread(threading.Thread):
  def __init__(self):
    super(SortingThread,self).__init__()
    self.numbers=GenerateNumbers(1,100)
  def run(self):
    self.numbers.sort()

if __name__=='__main__':
  #Parallel sort with multiple threads
  #
  sortingThreads=[]
  for i in xrange(k):
    sortingThreads.append(SortingThread())
  for i in xrange(k):
    sortingThreads[i].start()
  for i in xrange(k):
    sortingThreads[i].join()
    print i,sortingThrads[i].numbers
    
    #use heap to output the final sorted list.
    #We fill the heap with serval numbers firstly
    #
    theHeap=[]
    for i in xrange(1):
      for t in xrange(len(sortingThreads)):
        number=sortingThreads[t].numbers[i]
        heapq.heappush(theHeap,number)
    
    sortedNumbers=[]
    #In the while loop,people may replace the code by reading file routeings.
    #Since IO is always the bottleneck,so single thread should be enough
    p=1
    while (len(theHeap)>0):
      if p<len(sortingThreads[t].numbers):
        for t in xrange(len(sortingThreads)):
          number=sortingThreads[t].numbers[p]
          heapq.heappush(theHeap,number)
        p+=1
      sortedNumbers.append(heappop(theHeap))
    #Done
    print sortedNumbers