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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 julian_date(year, month=1, day=1, hour=0, minute=0, second=0.0):
 """Given a proleptic Gregorian calendar date, return a Julian date float."""

    return julian_day(year, month, day) - 0.5 + (
        second + minute * 60.0 + hour * 3600.0) / DAY_S