params.require(...)

params = ActionController::Parameters.new({
  person: {
    name: "Francesco",
    age:  22,
    role: "admin"
  }
})

permitted = params.require(:person).permit(:name, :age)
permitted            # => #<ActionController::Parameters {"name"=>"Francesco", "age"=>22} permitted: true>
permitted.permitted? # => true

Person.first.update!(permitted)
# => #<Person id: 1, name: "Francesco", age: 22, role: "user">