pset6 I just don't understand what I have to do

Question

import csv
import sys

counter  = 0

def main():

if len(sys.argv) != 3:
    sys.exit("Usage: python dna.py data.csv sequence.txt")

# Open csv file and read it's contents into memory
str_sequence = {
"AGATC" : 0,
"TTTTTTCT" : 0,
"AATG" : 0,
"TCTAG" : 0,
"GATA" : 0,
"TATC" : 0,
"GAAA" : 0,
"TCTG" : 0
 }

dna_data = []

with open(sys.argv[1]) as file:
   reader = csv.DictReader(file)
   for row in reader:
      dna_data.append(row)
# Open the text file and read it's contents into memory

sequences = []

file2 = open(sys.argv[2])

for pie in file2:
    file2.read()
    sequences.append(pie)

countsss = get_strcounts()
print(countsss)

def get_strcounts(sequences, str_sequence):

for i in sequences:
    for pie in str_sequence:
          if (sequences[0:i] == str_sequence[pie]):
              counter += 1
    return counter

main()

I could really use some explanation about this problem set. I am having a hard time with this transition from C to python and I would appreciate the help. I am really not able to understand how I can get the highest consecutive counts of strs and how I am supposed to actually use the function. Because for now I am just printing out the count to see if my code is correct but it gives nothing in the output.