Pretty printing for unary elementwise functions

- Fixed type error message for binary elementwise functions

Author: ndgrigorian

dpctl/tensor/_elementwise_common.py

@@ -47,6 +47,12 @@ def __init__(self, name, result_type_resolver_fn, unary_dp_impl_fn, docs):
         self.unary_fn_ = unary_dp_impl_fn
         self.__doc__ = docs
 
+    def __str__(self):
+        return f"<UnaryElementwiseFunc '{self.name_}'>"
+
+    def __repr__(self):
+        return f"<UnaryElementwiseFunc '{self.name_}'>"
+
     def __call__(self, x, out=None, order="K"):
         if not isinstance(x, dpt.usm_ndarray):
             raise TypeError(f"Expected dpctl.tensor.usm_ndarray, got {type(x)}")
@@ -389,7 +395,7 @@ def __call__(self, o1, o2, out=None, order="K"):
 
         if res_dt is None:
             raise TypeError(
-                "function 'add' does not support input types "
+                f"function '{self.name_}' does not support input types "
                 f"({o1_dtype}, {o2_dtype}), "
                 "and the inputs could not be safely coerced to any "
                 "supported types according to the casting rule ''safe''."