Take an array which consists of numbers or arrays, output if it only contains
Output should be a truthy or falsey value (Sorry if this destroys answers)
Truthy Test Cases
 [2,2] [,[2,2],2]  [,]
Falsey Test Cases
  [2,2,2,1] [[1,2],2]
Standard Loopholes Are forbidden.
Default IO rules apply.
Code-golf, Fewest bytes wins!