help with sons homework

[shadow]

He has the following code but he is getting the following error nboundLocalError: local variable 'grade' referenced before assignment, can anyone help please?

    def grade(overallmarks):
    percentage = overallmarks/150*100
# Prints 'No Award' if the overall percentage mark is less than 45
    if percentage <45:. 
        grade = "No Award"

# Prints the grade 'D' if the overall percentage mark is between 45 & 49
    elif percentage >= 45 and percentage <= 49:
        grade = "D"

# Prints the grade 'C' if the overall percentage mark is between 50 & 59
    elif percentage >= 50 and percentage <= 59:
        grade = "C"

# Prints the grade 'B' if the overall percentage mark is between 60 & 69
    elif percentage >= 60 and percentage <= 69:
        grade = "B"

# Prints the grade 'A' if the overall percentage mark is 70 or over
    elif percentage >=70:
        grade = "A"
        

    return grade, percentage


def main():
    
# Opens the studentgrades.csv file in read mode
    f = open("studentgrades.csv")
# Reads all of the file lines and put them in a list
    rows = f.readlines()

# The loop goes through all of the rows, one by one
    for counter in range(len(rows)):
    # Extract the current line
        line = rows[counter].strip()
    # Splits and organises each line and saves in a list
        fields = line.split(",") 

        student_name = fields[0]
        coursework = fields[1]
        prelim_mark = fields[2]
    # Set coursework to integer
        coursework = int(coursework)
    # Set prelim mark to integer
        prelim_mark = int(prelim_mark)
    # Sets overallmarks variable to coursework add prelim mark
        overallmarks = coursework + prelim_mark

        finalgrade, finalpercentage = grade(overallmarks)
        
    # Prints a line of 30 '*' to organise the data
        print(30 * "*")
    # Prints the student name from external file
        print("Student:", student_name)
    # Prints the students final percentage 
        print("Percentage:", finalpercentage)
    # Prints the students final grade
        print("Final Grade:", finalgrade)
    # Prints a blank line
        print()
        
# Boilerplate code
if __name__ == '__main__':
    main()

Output:
errorinal Grade: No Award

******************************
Student: Shahida Choudry
Percentage: 70.0
Final Grade: A

******************************
Student: Ian Li
Percentage: 50.0
Final Grade: C

******************************
Student: Petra Carter
Percentage: 39.33333333333333
Final Grade: No Award

Error:
Traceback (most recent call last):
  File "C:\Users\~XPS~\Desktop\student_grades.py", line 66, in <module>
    main()
  File "C:\Users\~XPS~\Desktop\student_grades.py", line 51, in main
    finalgrade, finalpercentage = grade(overallmarks)
  File "C:\Users\~XPS~\Desktop\student_grades.py", line 24, in grade
    return grade, percentage
UnboundLocalError: local variable 'grade' referenced before assignment

[Larz60+]

Indent error line 1,
period at end of line 4,
define:
grade = None
immediately after the def on line 1 (after correction indent)