input: from typing import List, Any
  
  def extract_words(sentence: str, letter: str) -> List[str]:
      """ Extract all the words in the given sentence that start with the specified letter.
      >>> extract_words('This is a sample sentence to test the program', 's')
      ['sample', 'sentence', 'test', 'the']
      >>> extract_words('Python programming is fun and easy', 'p')
      ['Python', 'programming']
      """
      words_list = [w for w in sentence.split() if w.lower().startswith(letter.lower())]
      return words_list
output:     words_list = [w for w in sentence.split() if w.lower().startswith(letter.lower())]
      return words_list