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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 list_files(tag=None, sat_id=None, data_path=None, format_str=None):
 """Produce a fake list of files spanning a year"""

    
    index = pds.date_range(pysat.datetime(2017,12,1), pysat.datetime(2018,12,1)) 
    # file list is effectively just the date in string format - '%D' works only in Mac. '%x' workins in both Windows and Mac
    names = [ data_path+date.strftime('%Y-%m-%d')+'.nofile' for date in index]
    return pysat.Series(names, index=index)