import com.google.common.base.CaseFormat;
import com.google.common.collect.ImmutableList;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.Locale;

```Python
say_hi(name=None)  # This works, None is valid 🎉
```

Tin tốt là, khi bạn sử dụng Python 3.10, bạn sẽ không phải lo lắng về điều đó, bạn sẽ có thể sử dụng `|` để định nghĩa hợp của các kiểu dữ liệu một cách đơn giản:

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009c_py310.py!}
```

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkElementIndex;
import static com.google.common.base.Preconditions.checkNotNull;
import static java.lang.System.arraycopy;
import static java.util.Collections.emptyMap;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Objects;

import java.util.List;
import java.util.stream.Collectors;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.core.beans.util.BeanUtil;
import org.codelibs.core.lang.StringUtil;
import org.codelibs.fess.Constants;
import org.codelibs.fess.app.pager.ElevateWordPager;
import org.codelibs.fess.es.client.SearchEngineClient;
import org.codelibs.fess.es.config.cbean.ElevateWordCB;

import java.io.IOException;
import java.io.InputStream;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.core.beans.util.BeanUtil;
import org.codelibs.core.lang.StringUtil;
import org.codelibs.fess.Constants;
import org.codelibs.fess.annotation.Secured;
import org.codelibs.fess.app.pager.ProtwordsPager;
import org.codelibs.fess.app.service.ProtwordsService;

import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.core.lang.StringUtil;
import org.codelibs.fess.Constants;
import org.codelibs.fess.annotation.Secured;
import org.codelibs.fess.app.pager.FileConfigPager;
import org.codelibs.fess.app.service.FileConfigService;

import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.core.lang.StringUtil;
import org.codelibs.fess.Constants;
import org.codelibs.fess.annotation.Secured;
import org.codelibs.fess.app.pager.WebConfigPager;
import org.codelibs.fess.app.service.LabelTypeService;

import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.MapFeature;
import com.google.common.collect.testing.testers.MapEntrySetTester;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.EnumMap;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.LinkedHashMap;

import java.util.regex.Pattern;
import java.util.stream.Collectors;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.core.io.CloseableUtil;
import org.codelibs.core.lang.StringUtil;
import org.codelibs.core.misc.Pair;
import org.codelibs.fess.app.service.FailureUrlService;
import org.codelibs.fess.crawler.builder.RequestDataBuilder;
import org.codelibs.fess.crawler.client.CrawlerClient;

labels.dictId=Dictionary ID
labels.docId=Document ID
labels.endTime=End Time
labels.hq=hq
labels.inputs=Source
labels.jobLogging=Logging
labels.jobName=Name
labels.jobStatus=Status
labels.labelTypeIds=Labels
labels.lang=lang
labels.outputs=Target
labels.pos=POS
labels.purgeJobLogDay=Purge Job Log Before
labels.purgeUserInfoDay=Purge User Before
labels.reading=Reading
labels.roleTypeIds=Role ID
labels.scriptData=Script