The use of the return keyword is different in a Python function vs. a MATLAB function.
In a MATLAB function, the Left Hand Side (LHS) arguments define what needs to be defined within the function body prior to returning.
function y = foo(x) y = 1; end
If you use a return statement to end execution of the function early, you still are responsible for correctly populating the LHS argument list of the function
function y = foo(x) y = 1; return; y = 2; end
In this example, foo returns 1 as y because the function body defines y to be 1, before execution returns to the caller after the return statement.
In python, the return statement ends execution AND also defines what (if any) values are returned by a function, there is no output argument list in a python function definition.
def foo(x): return 1;
Because you need to use the return keyword in python to return values from a function, return tends to be a more heavily used construct than return in MATLAB function definitions.