module T::Private::Methods

def self.install_hooks(mod)
  return if @installed_hooks.include?(mod)
  @installed_hooks << mod
  if mod == TOP_SELF
    # self at the top-level of a file is weirdly special in Ruby
    # The Ruby VM on startup creates an `Object.new` and stashes it.
    # Unlike when we're using sig inside a module, `self` is actually a
    # normal object, not an instance of Module.
    #
    # Thus we can't ask things like mod.singleton_class? (since that's
    # defined only on Module, not on Object) and even if we could, the places
    # where we need to install the hooks are special.
    mod.extend(SingletonMethodHooks) # def self.foo; end (at top level)
    Object.extend(MethodHooks)       # def foo; end      (at top level)
    return
  end
  # See https://github.com/sorbet/sorbet/pull/3964 for an explanation of why this
  # check (which theoretically should not be needed) is actually needed.
  if !mod.is_a?(Module)
    return
  end
  if mod.singleton_class?
    mod.include(SingletonMethodHooks)
  else
    mod.extend(MethodHooks)
  end
  mod.extend(SingletonMethodHooks)
end