diff --git a/xarray/core/dataset.py b/xarray/core/dataset.py
index 4593fd62730..5341b6f3f6f 100644
--- a/xarray/core/dataset.py
+++ b/xarray/core/dataset.py
@@ -4772,9 +4772,7 @@ def expand_dims(
             if d in self.dims:
                 raise ValueError(f"Dimension {d} already exists.")
             if d in self._variables and not utils.is_scalar(self._variables[d]):
-                raise ValueError(
-                    f"{d} already exists as coordinate or" " variable name."
-                )
+                raise ValueError(f"{d} already exists as coordinate or variable name.")
 
         variables: dict[Hashable, Variable] = {}
         indexes: dict[Hashable, Index] = dict(self._indexes)
@@ -4801,7 +4799,7 @@ def expand_dims(
                 pass  # Do nothing if the dimensions value is just an int
             else:
                 raise TypeError(
-                    f"The value of new dimension {k} must be " "an iterable or an int"
+                    f"The value of new dimension {k} must be an iterable or an int"
                 )
 
         for k, v in self._variables.items():
diff --git a/xarray/core/indexing.py b/xarray/core/indexing.py
index d8727c38c48..04eb67b981e 100644
--- a/xarray/core/indexing.py
+++ b/xarray/core/indexing.py
@@ -1640,7 +1640,7 @@ def _oindex_set(self, indexer: OuterIndexer, value: Any) -> None:
         num_non_slices = sum(0 if isinstance(k, slice) else 1 for k in indexer.tuple)
         if num_non_slices > 1:
             raise NotImplementedError(
-                "xarray can't set arrays with multiple " "array indices to dask yet."
+                "xarray can't set arrays with multiple array indices to dask yet."
             )
         self.array[indexer.tuple] = value
 
diff --git a/xarray/plot/utils.py b/xarray/plot/utils.py
index 1d61c5afc74..b9855fcea23 100644
--- a/xarray/plot/utils.py
+++ b/xarray/plot/utils.py
@@ -870,7 +870,7 @@ def _infer_interval_breaks(coord, axis=0, scale=None, check_monotonic=False):
         if (coord <= 0).any():
             raise ValueError(
                 "Found negative or zero value in coordinates. "
-                + "Coordinates must be positive on logscale plots."
+                "Coordinates must be positive on logscale plots."
             )
         coord = np.log10(coord)