In CVXR package in R, I am getting error like "attempt to apply non-function"

Question

I have a convex objective function named "obj_lasso". The minimisation is with respect to a vector v1 of dimension (p=7). The minimisation is going for 500 iterations. That is, at each iteration, it should return a vector v1. For that I am using syntax

 result_lasso$getValue(v1) 

But it returns the following error :

"Error in result _lasso$getValue(v1) : attempt to apply non function"

after say 35 iterations.

Anyone please help how to overcome this issue. Thanks in advance.

I am attaching the script and error message also.

Before giving the code here is some remark :

1. lambda_opt and alpha_shape are two known scalars
2. y is a known row vector of dimension (n=500, known)
3. x is the known design matrix without intercept column of dimension (nxp i.e 500x7)
4. v1 should return as a column vector of dimension (p=7)
5. The following code is iterated 500 times(not necessarily our n and this count should match always) . Basically 500 copies of beta_hat_final3 are used in long run.
6. I am getting error at "final_lasso" line say after 35 iterations.

Now, here is the code for mentioned issue:

 library (CVXR)

v1 = CVXR:: Variable (p)

penalty_lasso = lambda_opt*(p_norm(v1,1))

l1= alpha_shape*(sum(x%*%v1))

z_1 = as.matrix(y)

l2 =alpha_shape*(sum((z_1*(exp(-(x%*%v1)))))
)

obj_lasso = l1+l2+penalty_lasso

prob_lasso = Problem (Minimize(obj_lasso))

result_lasso = solve(prob_lasso)

result_lasso

##to get that minimizer v1, I am using now this: 

final_lasso = result_lasso$getValue(v1)

final_lasso1 = as.matrix(final_lasso)

beta_hat_final3 = t(final_lasso1) ### as a row vector 

Here is the error message I am getting :

" Error in result_lasso$getValue(v1) : attempt to apply non-function".

please help . Thanks in advance.