Count how many articles in a string in python

articles.py

#!/usr/bin/python3
"""
Module that counts number of articles in a string
"""


def filter_articles(text):
    """Count how many articles (a, an, the) in a string

    Args:
        text: (str) string to search

    Return: number of articles in `text`
    """

    sum_a = text.lower().split().count('a')
    sum_an = text.lower().split().count('an')
    sum_the = text.lower().split().count('the')
    return sum_a + sum_an + sum_the

if __name__ == "__main__":
    text = input("Enter some text:\n")
    print()
    count = filter_articles(text)
    print("There are {} articles in the text.".format(count if count > 0 else "no"))