class_docstr: Replace AST nodes.
class_docstr_tok: ["Replace","AST","nodes","."]
code: def visit_Expr(self, node):
      # When replacing a placeholder with an entire statement, the replacement
      # must stand on its own and not be wrapped in an Expr.
      new_value = self.visit(node.value)
      if new_value is node.value:
          return node
      return new_value
  
imports: import ast
  import textwrap
  import gast
  from nvidia.dali._autograph.pyct import anno
  from nvidia.dali._autograph.pyct import ast_util
  from nvidia.dali._autograph.pyct import parser
  from nvidia.dali._autograph.pyct import qual_names
label_desc: Use image node_id 3 for calling the ReplaceTransformer obj's underlying member method code with example usage: obj.visit_Expr(node) and returns: new_value, node