docs: def terms_from_dict(source):
      """ Convert a dict representing a query to a string.
  
          Args:
              source -- A dict with query xpaths as keys and text or nested query dicts as values.
  
          Returns:
              A string composed from the nested query terms given.
  
      >>> terms_from_dict({'document': {'title': "Title this is", 'text': "A long text."}})
      '<document><text>A long text.</text><title>Title this is</title></document>'
  
      >>> terms_from_dict({'document/title': "Title this is", 'document/text': "A long text."})
      '<document><title>Title this is</title></document><document><text>A long text.</text></document>'
      """
      parsed = ''
      for xpath, text in source.items():
          if hasattr(text, 'keys'):
              parsed += term(terms_from_dict(text), xpath, escape=False)
          else:
              parsed += term(text, xpath)
      return parsed