text: function pairs(arr) {
     let searchKey = arr.pop()
  
      let result = {}
  
      for (let i = 0; i < arr.length; i++) {
          let token = arr[i].split(' ')
          let key = token[0]
          let value = token[1]
  
          result[key]=value
      }
  
      if(result.hasOwnProperty(searchKey)){
         console.log(result[searchKey])
      }else{
          console.log('None')
      }
  }
  
  pairs([
      '3 test',
      '3 test1',
      '4 test2',
      '4 test3',
      '4 test5',
      '43'
  
  ])