def process(self, context):
    text_line = context.element.strip()
    if not text_line:
      context.aggregate_to(empty_line_aggregator, 1)
    words = re.findall(r'[A-Za-z\']+', text_line)
    for w in words:
      context.aggregate_to(average_word_size_aggregator, float(len(w)))
    return words
Returns an iterator over the words of this element.
dataset/ETHPy150Open GoogleCloudPlatform/DataflowPythonSDK/google/cloud/dataflow/examples/wordcount.py/WordExtractingDoFn.process