sampleDoc = (
    'Document that I set is complete now. Document is great set. Is document is great complete document set is complete. Document is complete document is good but not complete.'
    .lower())
findWord = 'document'.lower()
wordToFind = 'set is complete'.lower()
splitList = sampleDoc.split(findWord)
splitList.pop(0)
for position, phrase in enumerate(splitList):
    if wordToFind in phrase:
        print(('Document Number', str(position + 1), '-> true'))
else:
    print(('Document Number', str(position + 1), '-> false'))
python соответствует целевому слову