code: def unpack(iterable, count, fill=None):
      
      iterable = list(enumerate(iterable))
      cnt = count if count <= len(iterable) else len(iterable)
      results = [iterable[i][1] for i in range(cnt)]
  
      # results[len(results):len(results)] = [fill for i in range(count-cnt)]
      results = merge(results, [fill for i in range(count-cnt)])
      return tuple(results)
docs: The iter data unpack function.
  
      Example 1:
          In[1]: source = 'abc'
          In[2]: a, b = safe_unpack(source, 2)
          In[3]: print(a, b)
          a b
  
      Example 2:
          In[1]: source = 'abc'
          In[2]: a, b, c, d = safe_unpack(source, 4)
          In[3]: print(a, b, c, d)
          a b None None