io.UnsupportedOperation: not readable

[navidmo]

i dont understand why i get this error,
thnks for your helping

import hashlib
import csv
input_file_name = 'c:/users/shervin/documents/pass.csv'
output_file_name = 'c:/users/shervin/documents/pass1.csv'

def hash_password_hack(input_file_name, output_file_name):
    source = []
    source_names = []
    with open(input_file_name,'r', newline='') as f, open(output_file_name, 'w',newline='') as f:
        reader = csv.reader(f)
        for row in reader:
            source.append(row[1])
            source_names.append(row[0])

    pass_hash = {}
    for i in range(1000, 10000):
        i_st = str(i)
        i_st = hashlib.sha256(i_st.encode("utf-8"))
        hashed = i_st.hexdigest()
        pass_hash[hashed] = i

    for h in range(0, len(source)):
        if source[h] in pass_hash:
            csv_output.writerow(source_names[h], pass_hash[source[h]])

hash_password_hack(input_file_name, output_file_name)

Output:
Traceback (most recent call last):
  File "C:/Users/shervin/Downloads/15233519514032056 (1).py", line 26, in <module>
    hash_password_hack(input_file_name, output_file_name)
  File "C:/Users/shervin/Downloads/15233519514032056 (1).py", line 11, in hash_password_hack
    for row in reader:
io.UnsupportedOperation: not readable