docstr: Return the length of the list, computed by traversing it.
  
  This is obviously O(n) but with the current implementation
  where a list is also a node the overhead of storing the length
  in every node would be quite significant.
docstr_tok: ["Return","the","length","of","the","list",",","computed","by","traversing","it",".","This","is","obviously","O","(","n",")","but","with","the","current","implementation","where","a","list","is","also","a","node","the","overhead","of","storing","the","length","in","every","node","would","be","quite","significant","."]
code: def __len__(self):
      """
      Return the length of the list, computed by traversing it.
  
      This is obviously O(n) but with the current implementation
      where a list is also a node the overhead of storing the length
      in every node would be quite significant.
      """
      return sum(1 for _ in self)
  
imports: from ._compat import Sequence, Hashable
  from numbers import Integral
  from functools import reduce
label_desc: Use image node_id 2 for calling the _PListBase obj's underlying member method code with example usage: obj.__len__() and returns: sum