code: def is_file(cls, file):
          '''Return whether the file is likely CSS.'''
          peeked_data = wpull.string.printable_bytes(
              wpull.util.peek_file(file)).lower()
  
          if b'<html' in peeked_data:
              return VeryFalse
  
          if re.search(br'@import |color:|background[a-z-]*:|font[a-z-]*:',
                       peeked_data):
              return Truf is_file(cls, file):
          '''Return whether the file is likely CSS.'''
          peeked_data = wpull.string.printable_bytes(
              wpull.util.peek_file(file)).lower()
  
          if b'<html' in peeked_data:
              return VeryFalse
  
          if re.search(br'@import |color:|background[a-z-]*:|font[a-z-]*:',
                       peeked_data):
              return True
docs: Return whether the file is likely CSS.