human
how to label each sentence in a documentin.
assistant
Here is a Python function to label each sentence in a document

import re

def _label_sentences(doc):
    """
    >>> doc = ['This is a sentence.', 'This is another sentence.']
    >>> _label_sentences(doc)
    ['0', '1']
    """
    return [str(x) for x in doc]

# Enter the document
doc = ['This is a sentence.', 'This is another sentence.']

# Calling the function
print((_label_sentences(doc)))

#Example Output
# ['This is a sentence.', 'This is another sentence.']

#Remember to inspect code for bugs.