code: def create_security_group(self, name, description, vpc_id=None):
          
          parameters = {"GroupName":  name, "GroupDescription": description}
          if vpc_id:
              parameters["VpcId"] = vpc_id
          query = self.query_factory(
              action="CreateSecurityGroup", creds=self.creds,
              endpoint=self.endpoint, other_params=parameters)
          d = query.submit()
          return d.addCallback(self.parser.create_security_group)
docs: Create security group.
  
          @param name: Name of the new security group.
          @param description: Description of the new security group.
          @param vpc_id: ID of the VPC to which the security group will belong.
          @return: A C{Deferred} that will fire with a truth value for the
              success of the operation.