import csv
import os.path

fileName=None

if __name__=="__main__":
    try:
        fileName=argv[1]
        isFile(fileName)
        pass
    except Exception as e:
        print("You must provide a valid filename as parameter")
        raise

def isFile(fileName):
    if(not os.path.isfile(fileName)):
        raise ValueError("You must provide a valid filename as parameter")

print fileName


def readCsvAndCountPercentPerFormItemFromGoogleForms(fileName):
    times={}
    totalRows=0
    with open(fileName,'r') as csvfile:

        csvReader=csv.reader(csvfile);

        for row in csvreader:

            value=row[1]

            if(value in times.values()):
                times[value]+=1
            else:
                times[value]=1

            totalRows+=1

        return calculateDictionaryAsPercent(times,totalRows)

def calculateDictionaryAsPercent(times,totalRows):

    if(totalRows==0):
        raise ValueError("The file does not contain any rows")

    for key,val in times.items():
            times[key]=(val/totalRows)*100

    return times


finalTimes=readCsvAndCountPercentPerFormItemFromGoogleForms(fileName)

print finalTimes

Traceback (most recent call last):
  File "csv.py", line 1, in <module>
    import csv
  File "/home/pcmagas/Kwdikas/python/csv.py", line 54, in <module>
    finalTimes=readCsvAndCountPercentPerFormItemFromGoogleForms(fileName)
  File "/home/pcmagas/Kwdikas/python/csv.py", line 26, in readCsvAndCountPercentPerFormItemFromGoogleForms
    with open(fileName,'r') as csvfile:
TypeError: coercing to Unicode: need string or buffer, NoneType found

if __name__=="__main__":
    try:
        fileName=argv[1]
        isFile(fileName)
        pass
    except Exception as e:
        print("You must provide a valid filename as parameter")
        raise