class Rack::QueryParser

def normalize_params(params, name, v, _depth=nil)

earlier versions of rack.
and should no longer be used, it is kept for backwards compatibility with
conflict, a ParameterTypeError is raised. The depth argument is deprecated
the structural types represented by two different parameter names are in
normalize_params recursively expands parameters into structural types. If 
def normalize_params(params, name, v, _depth=nil)
  _normalize_params(params, name, v, 0)
end