From dfb9f9399ad1046f5cc7f4959c18e30bc0314266 Mon Sep 17 00:00:00 2001
From: Gregory Gundersen <ggundersen@gmail.com>
Date: Mon, 23 Sep 2019 22:08:38 -0400
Subject: [PATCH] Removed unused import.

---
 xarray/core/dataset.py | 6 +++++-
 xarray/core/utils.py   | 9 +++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/xarray/core/dataset.py b/xarray/core/dataset.py
index ea087ce3ce1..f633a3ded99 100644
--- a/xarray/core/dataset.py
+++ b/xarray/core/dataset.py
@@ -1999,7 +1999,11 @@ def sel(
         Dataset.isel
         DataArray.sel
         """
-        indexers = either_dict_or_kwargs(indexers, indexers_kwargs, "sel")
+        func_args = set(locals().keys())
+        dims = set(self.dims)
+        indexers = either_dict_or_kwargs(
+            indexers, indexers_kwargs, "sel", func_args=func_args, dims=dims
+        )
         pos_indexers, new_indexes = remap_label_indexers(
             self, indexers=indexers, method=method, tolerance=tolerance
         )
diff --git a/xarray/core/utils.py b/xarray/core/utils.py
index 0d730edeaeb..863f85d8d35 100644
--- a/xarray/core/utils.py
+++ b/xarray/core/utils.py
@@ -249,7 +249,16 @@ def either_dict_or_kwargs(
     pos_kwargs: Optional[Mapping[Hashable, T]],
     kw_kwargs: Mapping[str, T],
     func_name: str,
+    func_args: Any = None,
+    dims: Any = None,
 ) -> Mapping[Hashable, T]:
+    if func_args is not None:
+        inter = func_args.intersection(dims)
+        if inter:
+            raise ValueError(
+                "the dimension name '%s' matches an argument "
+                "to .%s" % (inter.pop(), func_name)
+            )
     if pos_kwargs is not None:
         if not is_dict_like(pos_kwargs):
             raise ValueError(