Django Function to remove characters from column, keep only number and cast it as integer

function.py

class ExtractInteger(Func):
    """Returns the first int value from the string. Note that this
    requires the string to have an integer value inside.
    
    Example of usage:
    YourModel.objects.filter(something=True).annotate(integer_value=ExtractInteger("field_name")).order_by("-integer_value")
    
    """

    function = "REGEXP_MATCH"
    template = "CAST((%(function)s(%(expressions)s, '\d+'))[1] as INTEGER)"
    output_field = IntegerField()