Use new TestValueError when available (#4179)

Co-authored-by: Brandon T. Willard <[email protected]>

Author: brandonwillard

pymc3/distributions/multivariate.py

@@ -38,6 +38,12 @@
 from .shape_utils import to_tuple
 from ..math import kron_dot, kron_diag, kron_solve_lower, kronecker
 
+# TODO: Remove this once the theano-pymc dependency is above 1.0.9
+try:
+    from theano.gof.utils import TestValueError
+except ImportError:
+    TestValueError = AttributeError
+
 
 __all__ = [
     "MvNormal",
@@ -477,7 +483,7 @@ def __init__(self, a, transform=transforms.stick_breaking, *args, **kwargs):
             )
             try:
                 kwargs["shape"] = np.shape(get_test_value(a))
-            except AttributeError:
+            except TestValueError:
                 pass
 
         super().__init__(transform=transform, *args, **kwargs)