# Time-based

{% hint style="success" %}
This is the official documentation of the `forestadmin-agent-django` and `forestadmin-agent-flask` Python agents.
{% endhint %}

![Time-based Chart example](https://2921382565-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HgnlEINLUAEQC1KgN48%2Fuploads%2Fgit-blob-253eb57c97ada0f165298b7694909f94cca88898%2Fchart-time.png?alt=media)

Time-based charts are very similar to distribution charts, the only differences being that:

* An additional parameter tells the frontend if the dates should be displayed by `Day`, `Week`, `Month`, or `Year`,
* The keys of the returned object can be ISO-8601 compliant string dates, python `datetime.date` object, or python `datetime.datetime` object.

```python
from datetime import date, datetime
from forestadmin.datasource_toolkit.context.agent_context import AgentCustomizationContext
from forestadmin.datasource_toolkit.decorators.chart.result_builder import ResultBuilder
from forestadmin.datasource_toolkit.interfaces.chart import Chart

async def transaction_volume_chart_fn(
    context: AgentCustomizationContext, result_builder: ResultBuilder
) -> Chart:
    return result_builder.timeBased(
        "Month",
        {
            '2017-02-01': 636,
            date(2017, 3, 1): 740,
            datetime(2017, 4, 1, 0, 0): 648,
            '2017-05-01': 726,
    })

agent.add_chart("transactionVolume", transaction_volume_chart_fn)
```

If you want to add several lines to the same chart, you can use the `multiple_time_based` method:

```python
from datetime import date, datetime
from forestadmin.datasource_toolkit.context.agent_context import AgentCustomizationContext
from forestadmin.datasource_toolkit.decorators.chart.result_builder import ResultBuilder
from forestadmin.datasource_toolkit.interfaces.chart import Chart

async def new_users_by_project(
    context: AgentCustomizationContext, result_builder: ResultBuilder
) -> Chart:
      # [...]

      return result_builder.multipleTimeBased(
          "Month"
          [
              date(2017, 2, 28),
              datetime(2017, 3, 28),
              '2017-04-28',
              '2017-05-28',
          ],
          [
              {"label": 'Project 1', "values": [636, 740, 648, 726]},
              {"label": 'Project 2', "values": [100, 200, 300, 400]},
          ],
      )

agent.add_chart('newUsersByProject', new_users_by_project)
```