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 specified separator/delimiter.
      >>> concatenate_strings(["Sample","Text","Hello"], " ")
      'Sample Text Hello'
      >>> concatenate_strings(["Sample","Text","Hello"], ",")
      'Sample,Text,Hello'
      """
      return separator.join(strings)
output:     return separator.join(strings)