Calculate Levenshtein distance between two strings in Python
There is a module available for exactly that calculation, python-Levenshtein. You can install it with pip install python-Levenshtein.

It is implemented in C, so is probably faster than anything you can come up with yourself.

from Levenshtein import distance as levenshtein_distance




According to the docstring conventions, your docstring should look like this, i.e. with the indentation aligned to the """ and the line length curtailed to 80 characters.

def calculate_levenshtein_distance(str_1, str_2):
    """
    The Levenshtein distance is a string metric for measuring the difference
    between two sequences.
    It is calculated as the minimum number of single-character edits necessary to
    transform one string into another.
    """
    ...