input: def rewrite_code_with_comprehensions(code: str) -> str:
      """ Rewrite the given Python code by introducing list comprehensions.
      >>> rewrite_code_with_comprehensions("""even_numbers = []
      for i in range(1,21):
          if i % 2 == 0:
              even_numbers.append(i)""")
      '[i for i in range(1, 21) if i % 2 == 0]'
      """
output:     lines = code.strip().split('\n')
      result = []
      for line in lines:
          if 'for' in line and 'in' in line and 'range' in line:
              start = line.find('for')
              end = line.find(':')
              for_part = line[start:end]
              if_part = ''
              append_part = ''
              if 'if' in line:
                  start = line.find('if')
                  end = line.find(':', start)
                  if_part = line[start:end]
              if '.append(' in line:
                  start = line.find('.append(') + len('.append(')
                  end = line.rfind(')')
                  append_part = line[start:end]
              result.append(f'[{append_part} {for_part} {if_part}]')
      return '\n'.join(result)