public function removeCoreError($env, $error = 0)
    {
        $this->swapArgs($env, $error, $this->running_env);
        
        $is_removed = false;
        if (isset($this->errors[$env])) {
            $orig = $this->errors[$env];
            $this->errors[$env] = ($this->errors[$env] & ~ $error);
            $is_removed = $this->errors[$env] !== $orig;
        }
        
        return $is_removed;
    }