code: def verify_signature(self, signedtext, cert_file=None, cert_type='pem', node_name=NODE_NAME, node_id=None, id_attr=''):
          
          # This is only for testing purposes, otherwise when would you receive
          # stuff that is signed with your key !?
          if not cert_file:
              cert_file = self.cert_file
              cert_type = self.cert_type
  
          if not id_attr:
              id_attr = self.id_attr
  
          return self.crypto.validate_signature(
                  signedtext,
                  cert_file=cert_file,
                  cert_type=cert_type,
                  node_name=node_name,
                  node_id=node_id,
                  id_attr=id_attr)
docs: Verifies the signature of a XML document.
  
          :param signedtext: The XML document as a string
          :param cert_file: The public key that was used to sign the document
          :param cert_type: The file type of the certificate
          :param node_name: The name of the class that is signed
          :param node_id: The identifier of the node
          :param id_attr: The attribute name for the identifier, normally one of
              'id','Id' or 'ID'
          :return: Boolean True if the signature was correct otherwise False.