docs: def FOR(self, node):
          """Process bindings for loop variables."""
          vars = []
  
          def collectLoopVars(n):
              if isinstance(n, ast.Name):
                  vars.append(n.id)
              elif isinstance(n, ast.expr_context):
                  return
              else:
                  for c in ast.iter_child_nodes(n):
                      collectLoopVars(c)
  
          collectLoopVars(node.target)
          for varn in vars:
              if (isinstance(self.scope.get(varn), Importation)
                      # unused ones will get an unused import warning
                      and self.scope[varn].used):
                  self.report(messages.ImportShadowedByLoopVar,
                              node, varn, self.scope[varn].source)
  
          self.handle_children(node)