CVX Keyword Semidefinite is giving error

Here is my CVX code.I am using sedumi solver. It’s giving following error:
Undefined matrix structure type: semidefinite
Trying to declare multiple variables? Use the VARIABLES keyword instead.

I tried using Variables instead of variable… It’s giving a new error.
Can anyone tell me what’s wrong with this code?
Thanks in advance

cvx_begin sdp
cvx_precision best
variable P(2,2) semidefinite
minimize 0
subject to
P >= 1*eye(2)
A1’P+PA1 <=0
A2’P+PA2 <=0
A3’P+PA3 <=0

Maybe it is the Version compatible problem. Try to use 'symmetric ’ instead of ‘semidefinite’

The original post is from 8 years ago. Whatever the difficulty was, it probably does not apply to any recent versions of CVX.