code: def flatten_strings(words1, words2):
      flat1 = []
      flat2 = []
      for seq in words1:
          flat1.extend(seq)
      stride = max((len(seq) for seq in words2), default=0)
      for seq in words2:
          flat2.extend(seq)
          flat2.extend([""] * (stride - len(seq)))
      return flat1, flat2
  
file_path: spacy-transformers/spacy_transformers/tests/test_alignment.py
imports: import pytest
  from typing import List
  import numpy
  from spacy.tokens import Doc
  from spacy.vocab import Vocab
  from thinc.api import NumpyOps
  from thinc.types import Ragged
  from ..align import get_alignment, apply_alignment
  from ..align import get_span2wp_from_offset_mapping
label_desc: Use image node_id 3 for calling a global function with example usage: flatten_strings(words1, words2) and returns: flat1,  flat2