class_docstr: An Overlay consists of multiple Elements (potentially of
  heterogeneous type) presented one on top each other with a
  particular z-ordering.
  
  Overlays along with elements constitute the only valid leaf types of
  a Layout and in fact extend the Layout structure. Overlays are
  constructed using the * operator (building an identical structure
  to the + operator).
docstr: Collates any objects in the Overlay resolving any issues
  the recommended nesting structure.
docstr_tok: ["Collates","any","objects","in","the","Overlay","resolving","any","issues","the","recommended","nesting","structure","."]
code: def collate(self):
      """
      Collates any objects in the Overlay resolving any issues
      the recommended nesting structure.
      """
      return reduce(lambda x, y: x * y, self.values())
  
imports: from functools import reduce
  import numpy
  import param
  from .dimension import Dimension, Dimensioned, ViewableElement, ViewableTree
  from .layout import AdjointLayout, Composable, Layout, Layoutable
  from .ndmapping import UniformNdMapping
  from .util import dimensioned_streams, sanitize_identifier, unique_array
label_desc: Use image node_id 4 for calling the Overlay obj's underlying member method code with example usage: obj.collate() and returns: reduce