working with in filename we then open the file and store the resulting file object in nextwe call csv reader(and pass it the file object as an argument to create reader object associated with that file we store the reader object in reader the csv module contains next(functionwhich returns the next line in the file when passed the reader object in the preceding listing we call next(only once so we get the first line of the filewhich contains the file headers we store the data that' returned in header_row as you can seeheader_row contains meaningful weather-related headers that tell us what information each line of data holds['akdt''max temperaturef''mean temperaturef''min temperaturef''max dew pointf''meandew pointf''min dewpointf''max humidity'mean humidity'min humidity'max sea level pressurein'mean sea level pressurein'min sea level pressurein'max visibilitymiles'mean visibilitymiles'min visibilitymiles'max wind speedmph'mean wind speedmph'max gust speedmph''precipitationin'cloudcover'events'winddirdegrees'reader processes the first line of comma-separated values in the file and stores each as an item in list the header akdt represents alaska daylight time the position of this header tells us that the first value in each line will be the date or time the max temperaturef header tells us that the second value in each line is the maximum temperature for that datein degrees fahrenheit you can read through the rest of the headers to determine the kind of information included in the file the headers are not always formatted consistentlyspaces and units are in odd places this is common in raw data files but won' cause problem note printing the headers and their positions to make it easier to understand the file header dataprint each header and its position in the listhighs_lows py --snip-with open(filenameas freader csv reader(fheader_row next(readeru for indexcolumn_header in enumerate(header_row)print(indexcolumn_headerwe use enumerate( on the list to get the index of each itemas well as the value (note that we've removed the line print(header_rowin favor of this more detailed version downloading data