Fix: code quality issues (#167)

- Removed unnecessary comprehension

- Used literal syntax instead of function calls to create data structure

- Used literal syntax to create data structure

- added .deepsource.toml file

.deepsource.toml

@@ -0,0 +1,15 @@
+version = 1
+
+test_patterns = ["cf_xarray/tests/test_*.py"]
+
+exclude_patterns = [
+    "doc/**",
+    "ci/**"
+]
+
+[[analyzers]]
+name = "python"
+enabled = true
+
+  [analyzers.meta]
+  runtime_version = "3.x.x"

cf_xarray/accessor.py

@@ -191,7 +191,7 @@ def _apply_single_mapper(mapper):
     else:
         results = flat
 
-    nresults = any([bool(v) for v in [results]])
+    nresults = any(bool(v) for v in [results])
     if not nresults:
         if error:
             raise KeyError(
@@ -497,7 +497,7 @@ def _getattr(
         if not attribute:
             return dict(attribute)
 
-        newmap = dict()
+        newmap = {}
         inverted = invert_mappings(
             accessor.axes,
             accessor.coordinates,
@@ -1165,7 +1165,7 @@ def cell_measures(self) -> Dict[str, List[str]]:
                 da.attrs.get("cell_measures", "") for da in obj.data_vars.values()
             ]
 
-        measures: Dict[str, List[str]] = dict()
+        measures: Dict[str, List[str]] = {}
         for attr in all_attrs:
             for key, value in parse_cell_methods_attr(attr).items():
                 measures[key] = measures.setdefault(key, []) + [value]
@@ -1201,7 +1201,7 @@ def standard_names(self) -> Dict[str, List[str]]:
         elif isinstance(self._obj, DataArray):
             variables = self._obj.coords
 
-        vardict: Dict[str, List[str]] = dict()
+        vardict: Dict[str, List[str]] = {}
         for k, v in variables.items():
             if "standard_name" in v.attrs:
                 std_name = v.attrs["standard_name"]

cf_xarray/tests/test_accessor.py

@@ -399,7 +399,7 @@ def test_dataarray_plot():
     plt.close()
 
     rv = obj.isel(lat=[0, 1], lon=1).cf.plot.line(x="T", hue="Y")
-    assert all([isinstance(line, mpl.lines.Line2D) for line in rv])
+    assert all(isinstance(line, mpl.lines.Line2D) for line in rv)
     plt.close()
 
     # set y automatically
@@ -517,7 +517,7 @@ def test_plot_xincrease_yincrease():
 @pytest.mark.parametrize("dims", ["lat", "time", ["lat", "lon"]])
 @pytest.mark.parametrize("obj", [airds])
 def test_add_bounds(obj, dims):
-    expected = dict()
+    expected = {}
     expected["lat"] = xr.concat(
         [
             obj.lat.copy(data=np.arange(76.25, 16.0, -2.5)),

cf_xarray/utils.py

@@ -51,5 +51,5 @@ def invert_mappings(*mappings):
     for mapping in mappings:
         for k, v in mapping.items():
             for name in v:
-                merged[name] |= set([k])
+                merged[name] |= {k}
     return merged