You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: propertyFunction_theta1_square.m
    path of file: ./repos/PESTO/examples/conversion_reaction
    
    the code of the file until where you have to start completion: function [f, grad_f, hess_f] = propertyFunction_theta1_square(theta)
% propertyFunction_theta1_square for examples/conversion_reaction
%
% returns the square of the first reaction rate as defined in 
% logLikelihood.m with derivatives
%
% Parameters: 
%  theta: Model parameters [theta_1, theta_2]'
%
% Return values:

    
function [f, grad_f, hess_f] = propertyFunction_theta1_square(theta)
% propertyFunction_theta1_square for examples/conversion_reaction
%
% returns the square of the first reaction rate as defined in 
% logLikelihood.m with derivatives
%
% Parameters: 
%  theta: Model parameters [theta_1, theta_2]'
%
% Return values:
%  f: double, value of property function
%  grad_f: double vector, gradient of property function
%  hess_f: double array, hessian of property function



%% Property Function Evaluation
f = theta(1)^2;
grad_f = [2*theta(1); 0];
hess_f = [2, 0; 0, 0];

end