Creating a new operator

• Must be inherited from TBaseOperator.

class MyTransform(TBaseOperator):

    def __init__(self, source: List[str], on_columns=None, how='left', **kwargs):
        super().__init__(**kwargs)
        self.source = source
    ...

• If there is a function parameter in the operator's constructor, then it must be called with the postfix * _callable.

For example:

class MyTransform(TBaseOperator):

    def __init__(self, py_callable,  **kwargs):
    ...