keep getting this out come "free variable 'valid_passport' referenced before assignment in enclosing scope" please help out

Question

def valid_passport(pp):

requirements = {"pid", "hgt", "cid", "iyr","byr","eyr","ecl","hcl", "ecl"} # Inputs all required keys into a list

return all(field in pp for field in requirements) or \

all(field in pp for field in requirements -{'ecl'}) # since the eye color is irrelevant, we define that here

def main():

pp_info = input("Enter the name of the file: ")

with open(pp_info, 'r') as file: # opens, reads and assigns the provided file

passports = file.read().split("\n\n") # correctly reads each passport information, acknowledging that each bit of information is separated by 2 blank lines

valid_passports = [pp for pp in passports if valid_passport(pp)]

print(f"There are {len(valid_passports)} valid passports")

with open(valid_passports.txt, 'w') as valid_file: # creates a new file with the intention of adding the information of the valid passports

for valid_passport in valid_passports:

valid_file.write(valid_passport + "\n\n") # inputs all the information of each valid passport, and separates them by 2 blank lines

if __name__ == "__main__":

main()

Answer 1

The problem is that you use the variable name "valid_passport" inside the for loop later in the function main. This means that within the method "main" "valid_passport" is a local variable that is different from the defined valid_passport method. The reason you are getting the "referenced before assignment" error is that you run the following line before the assignment of valid_passport (in the for loop).

valid_passports = [pp for pp in passports if valid_passport(pp)]

Solutions here are to change the name of the valid_passport method or to change the name of the variable valid_passport used in the for loop.