class_docstr: Base class for fixers which not execute if an import is found. 
class_docstr_tok: ["Base","class","for","fixers","which","not","execute","if","an","import","is","found","."]
code: def start_tree(self, *args):
      super(ConditionalFix, self).start_tree(*args)
      self._should_skip = None
  
imports: import itertools
  from .patcomp import PatternCompiler
  from .None import pygram
  from .fixer_util import does_tree_import
label_desc: Use image node_id 1 for calling the ConditionalFix obj's underlying member method code with example usage: obj.start_tree() without return types