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# atoti.Measure.isnull()

#### Measure.isnull()

Return a condition evaluating to `True` where this measure evalutes to `None`, and evaluating to `False` elsewhere.

### Example

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> df = pd.DataFrame(
...     columns=["City", "Price"],
...     data=[
...         ("Paris", 200.0),
...         ("Berlin", None),
...     ],
... )
>>> table = session.read_pandas(df, table_name="Example")
>>> cube = session.create_cube(table)
>>> l, m = cube.levels, cube.measures
>>> condition = m["Price.SUM"].isnull()
>>> condition
m['Price.SUM'].isnull()
>>> m["Price.isnull"] = condition
>>> m["Price.notnull"] = ~condition
>>> cube.query(
...     m["Price.SUM"],
...     m["Price.isnull"],
...     m["Price.notnull"],
...     levels=[l["City"]],
... )
       Price.SUM Price.isnull Price.notnull
City
Berlin                   True         False
Paris     200.00        False          True
```

* **Return type:**
  *RelationalCondition*\[TypeAliasForwardRef, Literal\[‘EQ’], NoneType]