Human: Write me a Python function to determine existence. Assistant: 
Here is a Python function to determine existence

import os

def is_pid_exist(pid):
    """
    Determine whether the pid exists or not.
    :param pid: pid
    :return: True or False
    """
    return os.path.exists(pid)

# Enter the pid
pid = "/home/rosey/Desktop/test.pid"

# Calling the function
print((is_pid_exist(pid)))

#Example Output
# False

#Remember to inspect code for bugs.