class_docstr: Yields the set of pure expressions
class_docstr_tok: ["Yields","the","set","of","pure","expressions"]
code: def visit_FunctionDef(self, node):
      if node in self.pure_functions:
          self.result.add(node)
  
      # do not visit arguments
      for stmt in node.body:
          self.visit(stmt)
  
file_path: pythran/pythran/analyses/pure_expressions.py
imports: from pythran.analyses.aliases import Aliases
  from pythran.analyses.argument_effects import ArgumentEffects
  from pythran.analyses.global_effects import GlobalEffects
  from pythran.analyses.pure_functions import PureFunctions
  from pythran.passmanager import ModuleAnalysis
  from pythran.intrinsic import Intrinsic
  import gast
label_desc: Use image node_id 2 for calling the PureExpressions obj's underlying member method code with example usage: obj.visit_FunctionDef(node) without return types