diff --git a/xarray/backends/h5netcdf_.py b/xarray/backends/h5netcdf_.py
index f2e3c556ce4..feadfcb4601 100644
--- a/xarray/backends/h5netcdf_.py
+++ b/xarray/backends/h5netcdf_.py
@@ -46,12 +46,6 @@ def _read_attributes(h5netcdf_var):
 _extract_h5nc_encoding = functools.partial(_extract_nc4_variable_encoding,
                                            lsd_okay=False, backend='h5netcdf')
 
-def _close_ds(ds):
-    # netCDF4 only allows closing the root group
-    ds = find_root(ds)
-    if not ds._closed:
-        ds.close()
-
 def _open_h5netcdf_group(filename, mode, group):
     import h5netcdf.legacyapi
     ds = h5netcdf.legacyapi.Dataset(filename, mode=mode)
@@ -162,5 +156,8 @@ def sync(self):
 
     def close(self):
         if self._isopen:
-            _close_ds(self.ds)
+            # netCDF4 only allows closing the root group
+            ds = find_root(self.ds)
+            if not ds._closed:
+                ds.close()
             self._isopen = False
diff --git a/xarray/backends/netCDF4_.py b/xarray/backends/netCDF4_.py
index b25e325f2aa..6c74f6981dc 100644
--- a/xarray/backends/netCDF4_.py
+++ b/xarray/backends/netCDF4_.py
@@ -177,12 +177,6 @@ def _extract_nc4_variable_encoding(variable, raise_on_invalid=False,
 
     return encoding
 
-def _close_ds(ds):
-    # netCDF4 only allows closing the root group
-    ds = find_root(ds)
-    if ds._isopen:
-        ds.close()
-
 
 def _open_netcdf4_group(filename, mode, group=None, **kwargs):
     import netCDF4 as nc4
@@ -342,5 +336,8 @@ def sync(self):
 
     def close(self):
         if self._isopen:
-            _close_ds(self.ds)
+            # netCDF4 only allows closing the root group
+            ds = find_root(self.ds)
+            if ds._isopen:
+                ds.close()
             self._isopen = False