code: def is_signature_line(line, sender, classifier):
      '''Checks if the line belongs to signature. Returns True or False.'''
      data = numpy.array(build_pattern(line, features(sender))).reshape(1, -1)
      return classifier.predict(data) > f is_signature_line(line, sender, classifier):
      '''Checks if the line belongs to signature. Returns True or False.'''
      data = numpy.array(build_pattern(line, features(sender))).reshape(1, -1)
      return classifier.predict(data) > 0
docs: Checks if the line belongs to signature. Returns True or False.