docs: def escape_string(text):
      """Remove problematic characters.
  
      Parameters
      ----------
      text
          A string with potentially problematic characters.
  
      Returns
      -------
      string
          The text with characters removed.
  
  
      Examples
      -------
      >>> s = r'hello_world$here'
      >>> escape_string(s) == r'helloworldhere'
      True
      """
      if text is None:
          return text
  
  
      TO_REMOVE = [r'&', r'%', r'$', r'#', r'_', r'{', r'}',
                   r'~', r'^', r'\\']
  
      for char in TO_REMOVE:
          text = text.replace(char, '')
      return text