c
int ossl_dsa_check_params(const DSA *dsa, int checktype, int *ret) {
    if (dsa == NULL) { 
        // Handle the error appropriately:
        //   - Set *ret to an error code 
        //   - Log the error
        //   - Return an error value 
        return 0; // Example: Returning 0 to indicate failure
    }

    // ... rest of the parameter checking logic ... 
}
