### Meer motivatie

Bekijk deze functie, deze heeft al type hints:

```Python hl_lines="1"
{!../../docs_src/python_types/tutorial003.py!}
```

Omdat de editor de types van de variabelen kent, krijgt u niet alleen aanvulling, maar ook controles op fouten:

<img src="/img/python-types/image04.png">

Nu weet je hoe je het moet oplossen, converteer `age` naar een string met `str(age)`:

```Python hl_lines="2"

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtIncompatible;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect.testing;

import static java.lang.System.arraycopy;

import com.google.common.annotations.GwtCompatible;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import static com.google.common.io.TestOption.CLOSE_THROWS;
import static com.google.common.io.TestOption.OPEN_THROWS;
import static com.google.common.io.TestOption.WRITE_THROWS;

import com.google.common.collect.ImmutableSet;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;

/** @author Colin Decker */

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.io.InvalidObjectException;

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Predicate;
import java.util.Map.Entry;
import java.util.Set;
import javax.annotation.CheckForNull;

import com.google.common.base.CharMatcher;
import com.google.common.base.Splitter;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Maps;
import com.google.common.io.ByteSource;
import com.google.common.io.CharSource;
import com.google.common.io.Resources;

import static java.nio.charset.StandardCharsets.US_ASCII;
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertThrows;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.common.hash.Hashing;
import com.google.common.primitives.UnsignedBytes;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

pkg iter, type Seq[$0 interface{}] func(func($0) bool) #61897
pkg maps, func All[$0 interface{ ~map[$1]$2 }, $1 comparable, $2 interface{}]($0) iter.Seq2[$1, $2] #61900
pkg maps, func Collect[$0 comparable, $1 interface{}](iter.Seq2[$0, $1]) map[$0]$1 #61900
pkg maps, func Insert[$0 interface{ ~map[$1]$2 }, $1 comparable, $2 interface{}]($0, iter.Seq2[$1, $2]) #61900

import static java.util.Objects.requireNonNull;

import com.google.common.annotations.Beta;
import com.google.common.base.Function;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.Immutable;

/**