Return dict with size of Ya.Disk. Keys: 'available', 'used'.

def df(self):
        """Return dict with size of Ya.Disk. Keys: 'available', 'used'."""

        def parseContent(content):
            root = ET.fromstring(content)
            return {
                'available': root.find(".//d:quota-available-bytes", namespaces=self.namespaces).text, 
                'used': root.find(".//d:quota-used-bytes", namespaces=self.namespaces).text
            }

        data = """
<D:propfind xmlns:D="DAV:">
  <D:prop>
    <D:quota-available-bytes/>
    <D:quota-used-bytes/>
  </D:prop>
</D:propfind>
        """
        resp = self._sendRequest("PROPFIND", "/", {'Depth': '0'}, data)
        if resp.status_code == 207:
            return parseContent(resp.content)
        else:
            raise YaDiskException(resp.status_code, resp.content)