Question - in strong_parameters is checking only key is present in params enough?

Hello,

This is just a question, wanted to understand why are we checking values are present for request params over checking if key is present in request.

  # File actionpack/lib/action_controller/metal/strong_parameters.rb, line 424
def require(key)
return key.map { |k| require(k) } if key.is_a?(Array)
value = self[key]
if value.present? || value == false
value
else
raise ParameterMissing.new(key)
end
end

so we can have params.require(:parameter).permit(:another_parameter)?

Thanks,

Sumit M