Return None instead of raising an exception on missing, valid emeter keys (#146)

Fixes #142

Also, update the pre-commit hooks to their newest versions

kasa/__init__.py

@@ -12,6 +12,7 @@ Module-specific errors are raised as `SmartDeviceException` and are expected
 to be handled by the user of the library.
 """
 from importlib_metadata import version  # type: ignore
+
 from kasa.discover import Discover
 from kasa.exceptions import SmartDeviceException
 from kasa.protocol import TPLinkSmartHomeProtocol

kasa/smartdevice.py

@@ -87,7 +87,8 @@ class EmeterStatus(dict):
                     if i.startswith(item):
                         return self.__getitem__(i) / 1000
 
-                raise SmartDeviceException("Unable to find a value for '%s'" % item)
+                _LOGGER.debug(f"Unable to find value for '{item}'")
+                return None
 
 
 def requires_update(f):

kasa/tests/test_emeter.py

@@ -115,3 +115,19 @@ async def test_current_consumption(dev):
         assert x >= 0.0
     else:
         assert await dev.current_consumption() is None
+
+
+async def test_emeterstatus_missing_current():
+    """KL125 does not report 'current' for emeter."""
+    from kasa import EmeterStatus
+
+    regular = EmeterStatus(
+        {"err_code": 0, "power_mw": 0, "total_wh": 13, "current_ma": 123}
+    )
+    assert regular["current"] == 0.123
+
+    with pytest.raises(KeyError):
+        regular["invalid_key"]
+
+    missing_current = EmeterStatus({"err_code": 0, "power_mw": 0, "total_wh": 13})
+    assert missing_current["current"] is None

kasa/tests/test_readme_examples.py

@@ -1,8 +1,8 @@
 import sys
 
 import pytest
-
 import xdoctest
+
 from kasa.tests.conftest import get_device_for_file