code: def create_security_group(self, name, description, vpc_id=None):
          
          params = {
              'GroupName': name,
              'GroupDescription': description
          }
  
          if vpc_id is not None:
              params['VpcId'] = vpc_id
  
          group = self.get_object('CreateSecurityGroup', params,
                                  SecurityGroup, verb='POST')
          group.name = name
          group.description = description
          return group
docs: Create a new security group for your account.
          This will create the security group within the region you
          are currently connected to.
  
          :type name: string
          :param name: The name of the new security group
  
          :type description: string
          :param description: The description of the new security group
  
          :type vpc_id: string
          :param vpc_id: The ID of the VPC to create the security group in,
                         if any.
  
          :rtype: :class:`boto.ec2.securitygroup.SecurityGroup`
          :return: The newly created :class:`boto.ec2.keypair.KeyPair`.