code: public MockSecurityGroup deleteSecurityGroup(final String securityGroupId) {
  
          if (securityGroupId != null && allMockSecurityGroup.containsKey(securityGroupId)) {
              return allMockSecurityGroup.remove(securityGroupId);
          }
  
          return null;
      }
docs: Delete MockSecurityGroup.
  
  @param securityGroupId
  securityGroupId to be deleted
  @return MockSecurityGroup.