Generates all possible pair combinations for the input list of sentences.

  For example:

  input = ["paraphrase1", "paraphrase2", "paraphrase3"]

  output = [("paraphrase1", "paraphrase2"),
            ("paraphrase1", "paraphrase3"),
            ("paraphrase2", "paraphrase3")]

  Args:
    list_of_sentences: the list of input sentences.
  Returns:
    the list of all possible sentence pairs.

def create_combination(list_of_sentences):
  """Generates all possible pair combinations for the input list of sentences.

  For example:

  input = ["paraphrase1", "paraphrase2", "paraphrase3"]

  output = [("paraphrase1", "paraphrase2"),
            ("paraphrase1", "paraphrase3"),
            ("paraphrase2", "paraphrase3")]

  Args:
    list_of_sentences: the list of input sentences.
  Returns:
    the list of all possible sentence pairs.
  """
  num_sentences = len(list_of_sentences) - 1
  combinations = []
  for i, _ in enumerate(list_of_sentences):
    if i == num_sentences:
      break
    num_pairs = num_sentences - i
    populated = num_pairs * [list_of_sentences[i]]
    zipped = list(zip(populated, list_of_sentences[i + 1:]))
    combinations += zipped
  return combinations