input: from typing import List
  
  
  def concatenate_strings(strings: List[str]) -> str:
      """ Concatenate a list of strings with a space in between each pair of strings.
      >>> concatenate_strings(["Hello", "World"])
      'Hello World'
      >>> concatenate_strings(["Python", "is", "fun"])
      'Python is fun'
      """
      return " ".join(strings)
output:     return " ".join(strings)