>>> def area(r,pi=3.14159): return pi *r*r >>> area

This is a function definition for calculating the area of a circle with radius `r` and optional value of `pi`, which is set to 3.14159 by default. However, the function is incomplete and requires a colon at the end of the first line. Here is the corrected code:

def area(r, pi=3.14159):
    return pi * r * r

Once you define this function, you can call it with a value for `r` like this:

print(area(5))  # Output: 78.53975

This will calculate the area of a circle with radius 5 using the default value of `pi`. You can also pass a different value for `pi` if you want, like this:

print(area(5, 3.14))  # Output: 78.5

This will calculate the area of a circle with radius 5 using a value of `pi` equal to 3.14.