class_docstr: Remove implicit tuple -> variable conversion.
  
  >>> import gast as ast
  >>> from pythran import passmanager, backend
  >>> node = ast.parse("def foo(): a=(1,2.) ; i,j = a")
  >>> pm = passmanager.PassManager("test")
  >>> _, node = pm.apply(NormalizeTuples, node)
  >>> print(pm.dump(backend.Python, node))
  def foo():
      a = (1, 2.0)
      i = a[0]
      j = a[1]
code: def visit_SetComp(self, node):
      return self.visit_AnyComp(node, "elt")
  
imports: from pythran.analyses import Identifiers
  from pythran.passmanager import Transformation
  import gast
  from functools import reduce
  from collections import OrderedDict
  from copy import deepcopy
label_desc: Use image node_id 7 for calling the NormalizeTuples obj's underlying member method code with example usage: obj.visit_SetComp(node) and returns: self