Use literal syntax instead of function calls to create the data structure

doc/whats-new.rst

@@ -146,6 +146,10 @@ Internal Changes
   ``all``, ``any``, ``enumerate``, ``sum``, ``tuple`` etc. can work directly with a
   generator expression. (:pull:`4026`)
   By `Prajjwal Nijhara <https://github.com/pnijhara>`_.
+- Use literal syntax instead of function calls to create the data structure
+  It is slower to call e.g. list() than using the empty literal, because the name list
+  must be looked up in the global scope in case it has been rebound. (:pull:`4038`)
+  By `Prajjwal Nijhara <https://github.com/pnijhara>`_.
 
 .. _whats-new.0.15.1:
 

xarray/core/merge.py

@@ -841,7 +841,7 @@ def merge(
     from .dataarray import DataArray
     from .dataset import Dataset
 
-    dict_like_objects = list()
+    dict_like_objects = []
     for obj in objects:
         if not isinstance(obj, (DataArray, Dataset, dict)):
             raise TypeError(

xarray/util/print_versions.py

@@ -129,7 +129,7 @@ def show_versions(file=sys.stdout):
         ("sphinx", lambda mod: mod.__version__),
     ]
 
-    deps_blob = list()
+    deps_blob = []
     for (modname, ver_f) in deps:
         try:
             if modname in sys.modules: