Review Callable usage

[zero323]

At least in some cases we can replace Callable with more precise Protocols.

[zero323]

#193 notwithstanding we have following ellipsed Callable:

pyspark-stubs/third_party/3/pyspark/sql/catalog.pyi

Line 31 in 16e085e

def registerFunction(self, name: str, f: Callable[..., Any], returnType: DataType = ...) -> None: ...

pyspark-stubs/third_party/3/pyspark/sql/context.pyi

Line 32 in 16e085e

def registerFunction(self, name: str, f: Callable[..., Any], returnType: DataType = ...) -> None: ...

pyspark-stubs/third_party/3/pyspark/sql/context.pyi

Line 64 in 16e085e

def register(self, name: str, f: Callable[..., Any], returnType: DataTypeOrString = ...) -> None: ...

pyspark-stubs/third_party/3/pyspark/sql/functions.pyi

Line 243 in 16e085e

func: Callable[..., Any]

pyspark-stubs/third_party/3/pyspark/sql/functions.pyi

Line 245 in 16e085e

def __init__(self, func: Callable[..., Any], returnType: DataTypeOrString, name: Optional[str] = ...) -> None: ...

pyspark-stubs/third_party/3/pyspark/sql/functions.pyi

Line 248 in 16e085e

def udf(f: Callable[..., Any], returnType: DataTypeOrString = ...) -> UserDefinedFunctionLike: ...

pyspark-stubs/third_party/3/pyspark/streaming/context.pyi

Line 36 in 16e085e

def transform(self, dstreams: List[DStream[Any]], transformFunc: Callable[..., RDD[T]]) -> DStream[T]: ...

where all, but the last one, are legacy udf related. Theoretically we can narrow things down a bit by enumerating all possible external types on argument and return type side (this wouldn't cover UDTs though), but it is probably not worth the effort, as application cannot be validated anyway.

The last option cannot be optimized, due to it's signature.

The remaining applications have been already addressed by 16c4a46