code: def union(seq1=(), *seqs):
      r
      if not seqs: return list(seq1)
      res = set(seq1)
      for seq in seqs:
          res.update(set(seq))
      return list(res)
docs: r"""Return the set union of `seq1` and `seqs`, duplicates removed, order random.
  
      Examples:
      >>> union()
      []
      >>> union([1,2,3])
      [1, 2, 3]
      >>> union([1,2,3], {1:2, 5:1})
      [1, 2, 3, 5]
      >>> union((1,2,3), ['a'], "bcd")
      ['a', 1, 2, 3, 'd', 'b', 'c']
      >>> union([1,2,3], iter([0,1,1,1]))
      [0, 1, 2, 3]