multiple if statements in SWIFT 3 :      @IBAction func addtoCart(_ sender: Any) {
        
        if  UserDataSingleton.sharedDataContainer.is_guest == "guest"  {
            
           //segue, user is a guest 
        }
        
        
        if sizebtn.isHidden == false {
        if Size.selectedItem == nil {
            // show alert , nothing is selected from items
            }

        } else {
        // do API call
                    
                } 
            
            }
            
        }
        }

The code above skips api calls if the user is not a guest and has selected something from item. How can I check if : 

1- user is not a guest 

2- if UIButton isn't hidden and user has selected from item 
