return total system memory in mebibytes (or None if parsing meminfo fails)

def get_total_memory():
    """return total system memory in mebibytes (or None if parsing meminfo fails)"""
    if platform.system() != "Linux":
        return None

    with open("/proc/meminfo", "r") as in_file:
        for line in in_file:
            info = line.split()
            if info[0] == "MemTotal:" and info[-1] == "kB":
                memory_mb = int(int(info[1]) / 1024)
                return memory_mb

    return None