title: generating a sequence incrementally in python
body: <pre><code>    def generator_zip(seq1, seq2, *more_seqs):
      if more_seqs==():
          t=min(len(seq1),len(seq2))
          for x in range(t):
            yield (seq1[x],seq2[x])
      else:
         t=min(len(seq1),len(seq2),len(more_seqs))
         for x in range(t+1):
             z=(seq1[x],seq2[x])+tuple([more_seqs[i][x] for i in range(len(more_seqs))])
             yield z
  
      assert [(1, 'a'), (2, 'b')] == list(generator_zip((1, 2), "abcd"))
      assert [(1, 'a', 1), (2, 'b', 2)] == list(generator_zip(range(1, 5), "abc", [1, 2]))
      list(generator_zip(range(1, 5), "abc", [1, 2],[1]))
  </code></pre>
  
  <p>but it is raising the error for the above conditon.
  what is the problem here?</p>