input: def find_words_with_consonants(s, n):
      """Given a string s and a natural number n, create a function that returns 
      a list of words from string s containing exactly n consonants, in the order 
      they appear in the string s.
      If the input string s is empty, the function should return an empty list.
      Note: assume the input string contains only letters and spaces.
      Examples:
      find_words_with_consonants("Mary had a little lamb", 4) ==> ["little"]
      find_words_with_consonants("Mary had a little lamb", 3) ==> ["Mary", "lamb"]
      find_words_with_consonants("simple white space", 2) ==> []
      find_words_with_consonants("Hello world", 4) ==> ["world"]
      find_words_with_consonants("Uncle sam", 3) ==> ["Uncle"]
      """
output:     if not s:
          return []
      
      vowels = set("aeiouAEIOU")
      words = s.split()
      
      result = []
      for word in words:
          consonant_count = sum(1 for char in word if char.isalpha() and char not in vowels)
          if consonant_count == n:
              result.append(word)
      
      return result