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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 is_running(process_id: int) -> bool: """ Uses the Unix ``ps`` program to see if a process is running. """

    pstr = str(process_id)
    encoding = sys.getdefaultencoding()
    s = subprocess.Popen(["ps", "-p", pstr], stdout=subprocess.PIPE)
    for line in s.stdout:
        strline = line.decode(encoding)
        if pstr in strline:
            return True
    return False