Gets the metadata XML from the provided URL

        :param url: Url where the XML of the Identity Provider Metadata is published.
        :type url: string

        :param validate_cert: If the url uses https schema, that flag enables or not the verification of the associated certificate.
        :type validate_cert: bool

        :returns: metadata XML
        :rtype: string

def get_metadata(url, validate_cert=True):
        """
        Gets the metadata XML from the provided URL

        :param url: Url where the XML of the Identity Provider Metadata is published.
        :type url: string

        :param validate_cert: If the url uses https schema, that flag enables or not the verification of the associated certificate.
        :type validate_cert: bool

        :returns: metadata XML
        :rtype: string
        """
        valid = False
        if validate_cert:
            response = urllib2.urlopen(url)
        else:
            ctx = ssl.create_default_context()
            ctx.check_hostname = False
            ctx.verify_mode = ssl.CERT_NONE
            response = urllib2.urlopen(url, context=ctx)
        xml = response.read()

        if xml:
            try:
                dom = fromstring(xml, forbid_dtd=True)
                idp_descriptor_nodes = OneLogin_Saml2_Utils.query(dom, '//md:IDPSSODescriptor')
                if idp_descriptor_nodes:
                    valid = True
            except Exception:
                pass

        if not valid:
            raise Exception('Not valid IdP XML found from URL: %s' % (url))

        return xml