@Deprecated
    public Properties getProperties() {
        return Stream
            .of(userProperties, classpathProperties)
            .reduce(
                new Properties(),
                (a, b) -> {
                    a.putAll(b);
                    return a;
                }
            );
    }
@return properties values available from user properties and classpath properties. Values set by environment
variable are NOT included.
@deprecated usages should be removed ASAP. See {@link TestcontainersConfiguration#getEnvVarOrProperty(String, String)},
{@link TestcontainersConfiguration#getEnvVarOrUserProperty(String, String)} or {@link TestcontainersConfiguration#getUserProperty(String, String)}
for suitable replacements.
core/src/main/java/org/testcontainers/utility/TestcontainersConfiguration.java