input: Write a python function to select authors from a list of book records where the book title contains the word 'python'.
  assert select_authors([{'author': 'Author1', 'title': 'Learning Python'}, {'author': 'Author2', 'title': 'Python Cookbook'}, {'author': 'Author3', 'title': 'Java Programming'}])==['Author1', 'Author2']
  assert select_authors([{'author': 'Author1', 'title': 'Python for Data Analysis'}, {'author': 'Author2', 'title': 'Effective Java'}, {'author': 'Author3', 'title': 'Python Machine Learning'}])==['Author1', 'Author3']
  assert select_authors([{'author': 'Author1', 'title': 'The C Programming Language'}, {'author': 'Author2', 'title': 'Fluent Python'}, {'author': 'Author3', 'title': 'Python Tricks'}])==['Author2', 'Author3']
output: def select_authors(book_records):
      return [book['author'] for book in book_records if 'python' in book['title'].lower()]