test for `array_find` fails

[clausmichele]

================================================================================ FAILURES ================================================================================
______________________________________________________________________ ArrayTester.test_array_find _______________________________________________________________________

self = <tests.test_arrays.ArrayTester testMethod=test_array_find>

>   ???

/home/mclaus@eurac.edu/openeo-processes-python/tests/test_arrays.py:124: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <xarray.DataArray (y: 5, x: 3)>
array([[False, False, False],
       [False, False, False],
       [False, False, Fals...lse, False]])
Coordinates:
  * y        (y) float64 55.3 56.3 57.3 58.3 59.3
  * x        (x) float64 118.9 119.9 120.9

    def __bool__(self: Any) -> bool:
>       return bool(self.values)
E       ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

../../anaconda3/envs/odc38/lib/python3.8/site-packages/xarray/core/common.py:131: ValueError