input: 
  def html_to_text(html_string):
      """ Convert a given HTML string to plain text by removing all tags and keeping only the text content.
      >>> html_to_text('<h1>Hello World</h1>')
      'Hello World'
      >>> html_to_text('This is <strong>bold</strong> and <em>italic</em> text.')
      'This is bold and italic text.'
      >>> html_to_text('<p>First paragraph</p><p>Second paragraph</p>')
      'First paragraphSecond paragraph'
      """
      output = ''
      in_tag = False
      for char in html_string:
          if char == '<':
              in_tag = True
          elif char == '>':
              in_tag = False
          elif in_tag == False:
              output += char
      return output
  
output:     output = ''
      in_tag = False
      for char in html_string:
          if char == '<':
              in_tag = True
          elif char == '>':
              in_tag = False
          elif in_tag == False:
              output += char
      return output