Why is this throwing: "TypeError: '_io.TextIOWrapper' object is not subscriptable"

def getnamesofstaff(file):      names_of_staff = []    print("file =",file)    for lines in file:       line = lines.strip().split(",")       name = line[0]       if name in names_of_staff:          breakpoint       else:          names_of_staff.append(name)    names_of_staff.sort(reverse=False)    return names_of_staff

def readfile(file):    f = open(file, "r")    return f

def output()    infile = enter_file.get()    input_file = "csvFiles\\" + infile +".csv"         ForFeesCovered.filecleaner(input_file)              f = ForFeesCovered.readfile(input_file)             list_from_file = csvEditor.editnewcsv(input_file)             csvEditor.makefinalcsv(list_from_file)                        f.close()    new_file = "Final Results\\Result.csv"              file = ForFeesCovered.readfile(new_file)            staff = ForFeesCovered.get_name_of_staff(file)      file.close()

ForFeesCovered.get_name_of_staff(): ForFeesCovered is another file that I have to code written in. Get_name_of_staff() is a function that takes in a CSV file and parses through it, pulling out all the staff names, throwing them into a list. For example, if the CSV file read "Adams, $0.5" Get_name_of_staff() would read the line and then pull out "Adams" and put it into a list.

These are the 3 functions that I am using. I am trying to open a CSV file and pull out the names in one of the columns. But whenever I run it. It throws this error "TypeError: '_io.TextIOWrapper' object is not subscriptable". I think this happens after reading the whole file. It tries to read the line after the end of the file which causes the program to throw the error.