input: Write a python function to detect plagiarism between two texts and return the percentage of similarity.
  assert detect_plagiarism("This is a sample text", "This is a sample text.") == 96.29629629629629
  assert detect_plagiarism("Hello world", "Hello World!") == 85.71428571428571
  assert detect_plagiarism("Python programming", "python programming") == 100.0
output: def detect_plagiarism(text1, text2):
      import difflib
      
      def clean_text(text):
          return ''.join(e for e in text if e.isalnum() or e.isspace()).lower()
      
      text1 = clean_text(text1)
      text2 = clean_text(text2)
      
      sequence = difflib.SequenceMatcher(None, text1, text2)
      return sequence.ratio() * 100