input: from typing import List
  
  
  def insert_delimiter_between_elements(numbers: List[int], delimiter: int) -> List[int]:
      """ Place a specified `delimiter` between each adjacent pair of elements in the list `numbers'
      >>> insert_delimiter_between_elements([], 4)
      []
      >>> insert_delimiter_between_elements([1, 2, 3], 4)
      [1, 4, 2, 4, 3]
      """
output:     if not numbers:
          return []
      
      result = []
      for i in range(len(numbers)):
          if i > 0:
              result.append(delimiter)
          result.append(numbers[i])
      
      return result