class_docstr: Gather variable that change in given node.
  
  It doesn't check constness as it is use for integer so we don't care about
  arguments effects as it is use by value.
docstr: Basic initialiser. 
docstr_tok: ["Basic","initialiser","."]
code: def __init__(self):
      """Basic initialiser."""
      self.result = list()
      super(IsAssigned, self).__init__()
  
imports: from pythran.passmanager import NodeAnalysis
  import gast
label_desc: Use image node_id 1 to create a new IsAssigned object from inherited base classes: NodeAnalysis with example: obj = IsAssigned()