Example with mandatory variables not filled in

---                                                                             
family1:                      # The first family                                
  var: example                                                                  
family2:                      # The second family                               
  var: example                                                                  
family3:                      # The third family with space                     
  var: example                # A variable                                      

Example with all modifiable variables

---                                                                             
family1:                      # The first family                                
  var: example                                                                  
family2:                      # The second family                               
  var: example                                                                  
family3:                      # The third family with space                     
  var: example                # A variable