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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def kill_process_from_pid_file_on_host(hostname, pid_file='app.pid'):
 """ Retrieves the PID of a process from a pid file on host and kills it. :param hostname: the hostname or ip address of the host on which the process will be killed :param pid_file: pid file to use holding the pid number to kill """

    status, pid = run_command_on_agent(hostname, 'cat {}'.format(pid_file))
    status, stdout = run_command_on_agent(hostname, "sudo kill -9 {}".format(pid))
    if status:
        print("Killed pid: {}".format(pid))
        run_command_on_agent(hostname, 'rm {}'.format(pid_file))
    else:
        print("Unable to killed pid: {}".format(pid))