Recursively apply a function to the elements of a list that
are themselves lists.
     
    
    Usage
    rlapply(x, fun, name_fun = NULL, ...)
 
    
    Arguments
    - x
- The list of lists to apply the function to 
- fun
- The function to apply to lists 
- name_fun
- Function used to name the elements of the returned list.
Should take a list as argument and return the name 
- ...
- arguments to pass to fun 
 
    
    Value
    
A one-level list where each element is the value fun returns for a
given list in x