human
Python functions to space to underscore the importance of space.
assistant
Here is a Python function to space to underscore the space

import pandas as pd

def space_to_underscore(s):
    """Convert space to underscore."""
    return s.replace(" ", "_")

# Enter the string
s = "Hello  world"

# Calling the function
print((space_to_underscore(s)))

#Example Output
# Hello__world

#Remember to inspect code for bugs.