class_docstr: Collector instances create children through collect()
  and thus iteratively build a tree.
docstr: returns a list of children (items and collectors)
  for this collection node.
docstr_tok: ["returns","a","list","of","children","(","items","and","collectors",")","for","this","collection","node","."]
code: def collect(self):
      """returns a list of children (items and collectors)
      for this collection node.
      """
      raise NotImplementedError("abstract")
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import warnings
  import py
  import six
  import _pytest._code
  from _pytest.compat import getfslineno
  from _pytest.mark.structures import NodeKeywords
  from _pytest.outcomes import fail
label_desc: Use image node_id 1 for calling the Collector obj's underlying member method code with example usage: obj.collect() without return types