Human: function that gives closest whole number. Assistant: 
Here is a Python code that gives the closest whole number

import math

def closest_whole_number(number):
    """Returns the closest whole number to `number`."""
    return int(round(number))

# Enter the number
number = 1.23456789

# Calling the function
print((closest_whole_number(number)))

#Example Output
# 1

#Remember to inspect code for bugs.