class Sass::Selector::Sequence

def merge_initial_ops(seq1, seq2)
  ops1, ops2 = [], []
  ops1 << seq1.shift while seq1.first.is_a?(String)
  ops2 << seq2.shift while seq2.first.is_a?(String)
  newline = false
  newline ||= !!ops1.shift if ops1.first == "\n"
  newline ||= !!ops2.shift if ops2.first == "\n"
  # If neither sequence is a subsequence of the other, they cannot be
  # merged successfully
  lcs = Sass::Util.lcs(ops1, ops2)
  return unless lcs == ops1 || lcs == ops2
  (newline ? ["\n"] : []) + (ops1.size > ops2.size ? ops1 : ops2)
end