brought back units with deprecation warning

Author: chenkasirer

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 * Changed `Tolerance` class to no longer use singleton pattern. `Tolerance()` now creates independent instances instead of returning the global `TOL`. 
+* Renamed `Tolerance.units` to `Tolerance.unit` to better reflect the documented properties. Left `units` with deprecation warning.
 
 ### Removed
 

src/compas/tolerance.py

@@ -34,6 +34,7 @@
 
 from contextlib import contextmanager
 from decimal import Decimal
+from warnings import warn
 
 import compas
 from compas.data import Data
@@ -443,6 +444,16 @@ def unit(self, value):
             raise ValueError("Invalid unit: {}".format(value))
         self._unit = value
 
+    @property
+    def units(self):
+        warn("The 'units' property is deprecated. Use 'unit' instead.", DeprecationWarning)
+        return self.unit
+
+    @units.setter
+    def units(self, value):
+        warn("The 'units' property is deprecated. Use 'unit' instead.", DeprecationWarning)
+        self.unit = value
+
     @property
     def absolute(self):
         if not self._absolute: