Client APIs
Null Handling
By default when functions receive a `NULL` value, this instantly returns `NULL`, as part of the default `NULL`-handling.
When this is not desired, you need to explicitly set this parameter to `"special"`.  
```python
import duckdb
from duckdb.typing import *

def dont_intercept_null(x):
return 5

duckdb.create_function("dont_intercept", dont_intercept_null, [BIGINT], BIGINT)
res = duckdb.sql("SELECT dont_intercept(NULL)").fetchall()
print(res)
```  
```text
[(None,)]
```  
With `null_handling="special"`:  
```python
import duckdb
from duckdb.typing import *

def dont_intercept_null(x):
return 5

duckdb.create_function("dont_intercept", dont_intercept_null, [BIGINT], BIGINT, null_handling="special")
res = duckdb.sql("SELECT dont_intercept(NULL)").fetchall()
print(res)
```  
```text
[(5,)]
```