def calculate_GWA(courses):
    GPA = 0.0
    units = 0.0
    for x in courses:
        if(x[2]== 'INC' or x[2]=='P' or x[2]=='F' or x[2]=='') or x[1].startswith('('):
            continue
        else:
            units += float(x[1])
            GPA += float(x[1])*float(x[2])
    if(GPA == 0 or units == 0):
        return ''
    else:
        return round(GPA/units,2)
 
my_grades_2 = [
    ('CS 298', '3.0', ''),
    ('CS 390', '3.0', '1.25'),('CS 390', '(3.0)', '5.0'),('CS 390', '3.0', '1.0'),('CS 390', '1.0', '1.25'),('CS 390', '10.0', '5'),('CS 390', '3.0', 'P'),('CS 390', '3.0', 'F'),('CS 390', '3.0', '')
]
 
gwa = calculate_GWA(my_grades_2) 
print(gwa) # must output 1.25

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