docs: def remove_matching_braces(latex):
      """
      If `latex` is surrounded by matching braces, remove them. They are not
      necessary.
  
      Parameters
      ----------
      latex : string
  
      Returns
      -------
      string
  
      Examples
      --------
      >>> remove_matching_braces('{2+2}')
      '2+2'
      >>> remove_matching_braces('{2+2')
      '{2+2'
      """
      if latex.startswith('{') and latex.endswith('}'):
          opened = 1
          matches = True
          for char in latex[1:-1]:
              if char == '{':
                  opened += 1
              elif char == '}':
                  opened -= 1
              if opened == 0:
                  matches = False
          if matches:
              latex = latex[1:-1]
      return latex