input: def rewrite_with_list_comprehensions(code_input: str) -> str:
      """Rewrite the given Python code by introducing list comprehensions.
      >>> rewrite_with_list_comprehensions("even_numbers = []\nfor i in range(1,21):\n    if i % 2 == 0:\n        even_numbers.append(i)")
      'even_numbers = [i for i in range(1, 21) if i % 2 == 0]'
      """
output:     lines = code_input.split('\n')
      new_lines = []
      for line in lines:
          if 'for' in line and 'in' in line and 'range' in line:
              for_line = line
              if_line = lines[lines.index(line) + 1]
              append_line = lines[lines.index(line) + 2]
              if 'if' in if_line and 'append' in append_line:
                  var = for_line.split()[1]
                  start, end = for_line.split('range')[1].strip('()').split(',')
                  condition = if_line.split('if')[1].strip()
                  new_line = f'{var} = [{var.split()[0]} for {var} in range({start}, {end}) if {condition}]'
                  new_lines.append(new_line)
              else:
                  new_lines.append(line)
          else:
              new_lines.append(line)
      return '\n'.join(new_lines)