def compute_grade(num_level1,num_level2,num_level3):
'''
Computes a grade for CSC/DSP310 from numbers of achievements at each level
Parameters:
------------
num_level1 : int
number of level 1 achievements earned
num_level2 : int
number of level 2 achievements earned
num_level3 : int
number of level 3 achievements earned
Returns:
--------
letter_grade : string
letter grade with modifier (+/-)
'''
if num_level1 == 15:
if num_level2 == 15:
if num_level3 == 15:
grade = 'A'
elif num_level3 >= 10:
grade = 'A-'
elif num_level3 >=5:
grade = 'B+'
else:
grade = 'B'
elif num_level2 >=10:
grade = 'B-'
elif num_level2 >=5:
grade = 'C+'
else:
grade = 'C'
elif num_level1 >= 10:
grade = 'C-'
elif num_level1 >= 5:
grade = 'D+'
elif num_level1 >=3:
grade = 'D'
else:
grade = 'F'
return grade
