def timeToMicrosecondFormat(time_str, nzeros=6):
    """Helper function to change the given time string to a microsecond precision."""
    dot = time_str.rfind(".")
    if dot < 0:
        return time_str + "." + "0" * nzeros
    else:
        return time_str + "0" * (nzeros - (len(time_str) - dot - 1))