code: public Variable remove(String name) {
          if (context.containsKey(name)) {
              return context.remove(name);
          } else {
              return null;
          }
      }
docs: Removes the variable with the given name from this scope.
  <p>
  If will not remove the variable from a parent scope.
  
  @param name the name of the variable to remove
  @return the removed variable or <tt>null</tt> if no variable with the given name existed