So, the code for the function is posted below:

```
# Add your function below!
def average(numbers):
total = sum(numbers)
total = float(total)
return total/len(numbers)
def get_average(student):
homework = average(student["homework"])
quizzes = average(student["quizzes"])
tests = average(student["tests"])
return 0.1 * homework + 0.3 * quizzes + 0.6 * tests
def get_letter_grade(score):
if score >= 90:
return "A"
elif score >=80:
return "B"
elif score >=70:
return "C"
elif score >=60:
return "D"
else:
return "F"
print get_letter_grade(get_average(lloyd))
```

My questions have to do with the terms â€śnumbersâ€ť and â€śscoreâ€ť within the functions being defined: since we have not defined â€śnumbersâ€ť or â€śscoreâ€ť, how does the computer know what they are? Are these terms already part of the Python language?