Question regarding ode45 function and scripts

So I have a script saved as, "Project_1a", within it are the following lines of code:

function dy = derives(t,y) 
g = 9.8;
dy = [y(2);-g];

In the command window, I have inputted the following lines:

g = 9.8;
h0 = 0;
v0 = 0;
[t,y]=ode45('Project_1a',[0:0.01:200],[h0 v0]);

Why does this work? In the sense, that I have been told that the script needs to match the function ie. the script needs to be saved as "derives". I made two scripts one called "Project_1a" and "derives" that have the same code as above and they both output the same array. Can anyone explain as to why they don't need to have the same name or if my code is just special occurrence that managed to work out?

Thanks