converge on cf-units to reduce code change

compliance_checker/cf/cf_1_6.py

@@ -827,7 +827,7 @@ def _check_valid_cf_units(self, ds, variable_name):
         # being expressed as "s"/seconds
         if standard_name not in {"time", "forecast_reference_time"}:
             valid_units.assert_true(
-                units_conv.is_convertible_to(cfutil._units(reference)),
+                units_conv.is_convertible(cfutil._units(reference)),
                 f'Units "{units}" for variable '
                 f"{variable_name} must be convertible to "
                 f'canonical units "{reference}"',
@@ -2849,7 +2849,7 @@ def _cell_measures_core(self, ds, var, external_set, variable_template):
                         valid = False
                         reasoning.append(conversion_failure_msg)
                     else:
-                        if not cell_measure_units.is_convertible_to(
+                        if not cell_measure_units.is_convertible(
                             cfutil._units(f"m{exponent}"),
                         ):
                             valid = False

compliance_checker/cfunits.py

@@ -12,9 +12,6 @@
 class CFUnitMixin:
     """Standardize the methods from cf-untis and pyudunits2 used in compliance-checker."""
 
-    def is_convertible_to(self, other):
-        return self.is_convertible(other)
-
     def expand_definition(self):
         return self.definition
 

compliance_checker/cfutil.py

@@ -2044,4 +2044,4 @@ def units_convertible(units1, units2):
         u2 = _units(units2)
     except ValueError:
         return False
-    return u1.is_convertible_to(u2)
+    return u1.is_convertible(u2)