code: def _dict_to_html_attributes(d):
          
          if d is None:
              return ""
  
          return "".join(" {}=\"{}\"".format(key, value) for key, value in iter(d.items()))
docs: Converts a dictionary to a string of ``key=\"value\"`` pairs.
          If ``None`` is provided as the dictionary an empty string is returned,
          i.e. no html attributes are generated.
  
          Parameters
          ----------
          d : dict
              Dictionary to convert to html attributes.
  
          Returns
          -------
          str
              String of HTML attributes in the form ``key_i=\"value_i\" ... key_N=\"value_N\"``,
              where ``N`` is the total number of ``(key, value)`` pairs.