My def functions are not being executed in Python : <pre><code>print("Welcome to the BMI Index Calculator.")    
student_name = " "    
while student_name != "0":    
     student_name = input("Please begin by entering the student's name, or 0 to quit:")    
     if student_name == "0":
        print("Exiting program...")
        exit()

     def student_height():
        input("Please enter student's height in inches:")
        return

     def student_weight():
        input("Please enter student's weight in pounds:")
        return

     def bmi_profile():
        print(student_name, "'s BMI profile:")
        print("Height:", student_height, '"')
        print("Weight:", student_weight, "lbs.")

     def bmi_index(bmi):
        bmi = (student_weight * 703 / student_height ** 2)
        print("BMI Index:", bmi)
        return bmi
</code></pre>

<p>The loop runs but the def functions are not being executed. Can someone tell me where is my mistake? I try to fix the indentation many times but apparently that's not the error...
Thank you in advance for the help.</p>
