docs: def to_list(self):
          '''Convert the source sequence to a list.
  
          Note: This method uses immediate execution.
          '''
          if self.closed():
              raise ValueError("Attempt to call to_list() on a closed Queryable.")
  
          # Maybe use with closable(self) construct to achieve this.
          if isinstance(self._iterable, list):
              return self._iterable
          lst = list(self)
          # Ideally we would close here. Why can't we - what is the problem?
          #self.close()
          return lst