parameters: (f, source)
docstring: alternate write & seek one unit
docstring_summary: alternate write & seek one unit
docstring_tokens: alternate write & seek one unit
function: def modify_seek_forward_bytewise(f, source):
      """ alternate write & seek one unit """
      f.seek(0)
      for i in xrange(0, len(source), 2):
          f.write(source[i:i+1])
          f.seek(i+2)
function_tokens: def modify_seek_forward_bytewise ( f , source ) : f . seek ( 0 ) for i in xrange ( 0 , len ( source ) , 2 ) : f . write ( source [ i : i + 1 ] ) f . seek ( i + 2 )