input: from typing import List
  
  
  def concatenate_strings(strings: List[str], separator: str) -> str:
      """
      Takes a list of strings and returns the concatenation of all the elements with a given separator/delimiter.
  
      >>> concatenate_strings(["Sample", "Text", "Hello"], "--")
      'Sample--Text--Hello'
      >>> concatenate_strings(["A", "B", "C"], "-")
      'A-B-C'
      """
output:     result = ""
      for i, s in enumerate(strings):
          result += s
          if i < len(strings) - 1:
              result += separator
      return result