Using if condition with assume,

I got the following error while I am using if condition with assume, so please any help: Too many output arguments with if condition, and assume

clear all; 
close all;
clc;
syms x y;
yin=[(solve(-1500<.2500*x+.7500*y+20.78,y)), 
(solve(.2500*x+.7500*y+20.78<1500,y))]
 % %@x=100
 yin2=[-100/3 - 152003/75, 147847/75 - 100/3]

 if assume(-2060<y & y<1938)
display('ok')
else
 display('nothing')
end 

I expect the output should be possible answers of the interval I added