deprecate derivatives and error_components

CHANGES.rst

@@ -17,6 +17,10 @@ Adds:
 
 Deprecates:
 
+- The `AffineScalarFunc.derivatives` property has been marked as deprecated. This
+   property will be removed in a future release.
+- The `AffineScalarFunc.error_components()` method has been marked as deprecated. This
+   method will be replaced by a property of the same name in a future release.
 - Support for interoperability between `uncertainties` `AffineScalarFunc` scalar objects
    and `np.matrix` objects is now marked as deprecated. According to the
    `numpy documentation <https://numpy.org/doc/stable/reference/generated/numpy.matrix.html>`_

uncertainties/core.py

@@ -445,6 +445,12 @@ def derivatives(self):
 
         This mapping is cached, for subsequent calls.
         """
+        warn(
+            f"{self.__class__.__name__}.derivatives() is deprecated. It will "
+            f"be removed in a future release.",
+            FutureWarning,
+            stacklevel=2,
+        )
 
         if not self._linear_part.expanded():
             self._linear_part.expand()
@@ -469,6 +475,15 @@ def error_components(self):
         object take scalar values (and are not a tuple, like what
         math.frexp() returns, for instance).
         """
+        warn(
+            f"{self.__class__.__name__}.error_components() is currently an "
+            f"instance method. This method is deprecated. In a future release it will "
+            f"be replaced with an instance property by the same name. It will be "
+            f"accessed by {self.__class__.__name__}.error_components (with no "
+            f"parentheses).",
+            FutureWarning,
+            stacklevel=2,
+        )
 
         # Calculation of the variance:
         error_components = {}