Does anyone know how to get rid of the “None” and “Sorry, invalid input” after the solution.

My code:

```
def area_of_triangle():
b = input("Base: ")
h = input("Height: ")
area = 0.5 * float(b) * float(h)
print("The area of the triangle is " + str(area) + ".")
def area_of_square():
l = input("Length: ")
w = input("Width: ")
area = int(l) * int(w)
print("The area of the square is " + str(area) + ".")
def area_of_circle():
r = input("Radius: ")
area = 3.14159 * float(r) ** 2
print("The area of the cirle is " + str(area) + ".")
def area_of_trap():
a = input("Base 1: ")
b = input("Base 2: ")
h = input("Height: ")
area = 0.5 * (float(a) + float(b)) * float(h)
print("The area of the trapeziod is " + str(area) + ".")
formula = input("Please type the equation you would like to do. If you dont know type help. ")
if formula == "triangle":
print(area_of_triangle())
if formula == "square":
print(area_of_square())
if formula == "circle":
print(area_of_circle())
if formula == "trapezoid":
print(area_of_trap())
if formula == "help":
print("To find the area of your shape in lowercase. Shapes: Triangle, square, circle, and trapezoid.")
else:
print("Sorry, invalid input.")
```

Output: