new_contents: import unittest
  import troposphere.ec2 as ec2
  
  
  class TestEC2(unittest.TestCase):
  
      def test_securitygroupegress(self):
          egress = ec2.SecurityGroupEgress(
              'egress',
              ToPort='80',
              FromPort='80',
              IpProtocol="tcp",
              GroupId="id",
              CidrIp="0.0.0.0/0",
          )
          egress.JSONrepr()
  
          egress = ec2.SecurityGroupEgress(
              'egress',
              ToPort='80',
              FromPort='80',
              IpProtocol="tcp",
              GroupId="id",
              DestinationPrefixListId='id',
          )
          egress.JSONrepr()
  
          egress = ec2.SecurityGroupEgress(
              'egress',
              ToPort='80',
              FromPort='80',
              IpProtocol="tcp",
              GroupId="id",
              DestinationSecurityGroupId='id',
          )
          egress.JSONrepr()
  
          egress = ec2.SecurityGroupEgress(
              'egress',
              ToPort='80',
              FromPort='80',
              IpProtocol="tcp",
              GroupId="id",
              CidrIp="0.0.0.0/0",
              DestinationPrefixListId='id',
          )
  
          with self.assertRaises(ValueError):
              egress.JSONrepr()
          egress = ec2.SecurityGroupEgress(
              'egress',
              ToPort='80',
              FromPort='80',
              IpProtocol="tcp",
              GroupId="id",
              CidrIp="0.0.0.0/0",
              DestinationPrefixListId='id',
              DestinationSecurityGroupId='id',
          )
  
          with self.assertRaises(ValueError):
              egress.JSONrepr()
  
subject: Add tests for SecurityGroupEgress