how to fix the following Python code

please run the code and tell me the output

there is red line under "assign_grade" what is the problem and how to fix it

letter_grade = assign_grade(score, student_type, curve_score)

this is the code:

def open_the_input_file(): # Prompt the user for the input file name filename = input('Please enter the name of the input file: ') # Open the file and return it return open(filename, 'r') def open_the_output_file(): # Prompt the user for the output file name filename = input('Please enter the name of the output file: ') # Open the file and return it return open(filename, 'w') def process_grade_data(input_file, output_file): # Prompt the user if they want to curve the grades curve_grades = input('Would you like to curve the grades? (Y/N) ').lower() == 'y' curve_score = None # If curving the grades, prompt the user for the curve score if curve_grades: curve_score = float(input('Please enter the score that should map to a "100%" grade: ')) # Process the input file and write the output file for line in input_file: student_type = line.strip() name = input_file.readline().strip() score_line = input_file.readline().strip() if not score_line: print('Error: missing score for student', name) continue try: score = float(score_line) letter_grade = assign_grade(score, student_type, curve_score) except ValueError as e: print('Error processing data for student {}: {}'.format(name, str(e))) print('Skipping this student.') continue output_file.write(name + ' ') output_file.write(letter_grade + ' ') print("All data was successfully processed and saved to the requested output file.") def main(): # Ask the user for the name of the input file and open it input_file = open_the_input_file() # Ask the user for the name of the output file and open it output_file = open_the_output_file() # Process the grade data process_grade_data(input_file, output_file) # Close both the input and output file input_file.close() output_file.close() # Call main to run your program. main()