Function not callable anymore after one try
Solution 1:
On the third-to-last line:
Psi = Psi(2e-16)
You are updating the reference to Psi from the function to the return value. Upon doing so, Psi can no longer be used as a function. It is advisory to never use variables with the same names as functions or classes in your code. Solutions are to either rename the variable, or rename the function and function call.