Pyspark vector classes always return error for unary negation

    def _delegate(op):
        def func(self, other):
            if isinstance(other, DenseVector):
                other = other.array
            return DenseVector(getattr(self.array, op)(other))
        return func

    __neg__ = _delegate("__neg__")

from pyspark.ml.linalg import DenseVector
v = DenseVector([1,2,3])
-v
...
TypeError: func() missing 1 required positional argument: 'other'