In Python, you can represent a negative duration using a timedelta object with negative arguments. For example, here's how you can create a timedelta object representing a duration of -1 day:

from datetime import timedelta
 
duration = timedelta(days=-1)
 
print('Duration:', duration)

In this code, we create a timedelta object representing a duration of -1 day by passing a negative value for the days argument to the timedelta() constructor. We then print the timedelta object using the print() function.

You can perform arithmetic operations on negative timedelta objects just like you can with positive timedelta objects. For example, you can add a negative duration to a datetime object to subtract time from it:

from datetime import datetime, timedelta
 
# Create a datetime object
datetime_obj = datetime(2023, 3, 14, 13, 30, 45)
 
# Define a negative duration of 1 day
negative_duration = timedelta(days=-1)
 
# Subtract the duration from the datetime object
new_datetime_obj = datetime_obj + negative_duration
 
print('New datetime object:', new_datetime_obj)

In this code, we subtract a duration of 1 day from a datetime object by creating a negative timedelta object with a value of -1 for the days argument, and then adding it to the datetime object using the + operator. The result is a new datetime object representing the same time 1 day earlier.