<｜begin▁of▁sentence｜>### Instruction:
In an imaginary Python function that requires an optional argument to be of either integer or float type (if provided), how would you utilize the 'graspologic.preconditions.check_optional_argument_types' utility to ensure that the provided argument adheres to these type constraints, while also accepting a 'None' value as valid?
### Response:
```python
import graspologic

# Initialize a function that uses check_optional_argument_types
def example_function(optional_arg=None):
    # Define the types that are allowed
    required_types = (int, float)
    
    # Use the check function to ensure the argument type is correct or None
    try:
        graspologic.preconditions.check_optional_argument_types(value=optional_arg, required_types=required_types, message='Optional argument must be of type int or float.')
        print('Valid type or None!')
    except TypeError as e:
        print(e)

# Test the function with valid types and None
example_function(optional_arg=3.14)
example_function(optional_arg=None)
example_function(optional_arg='string')
```
<|EOT|>
