REF: disambiguate get_loc_level k variable (#42378)

Author: jbrockmendel

pandas/core/generic.py

@@ -3765,18 +3765,12 @@ class   animal   locomotion
         self._consolidate_inplace()
 
         if isinstance(index, MultiIndex):
-            try:
-                loc, new_index = index._get_loc_level(key, level=0)
-            except TypeError as err:
-                raise TypeError(
-                    f"Expected label or tuple of labels, got {key}"
-                ) from err
-            else:
-                if not drop_level:
-                    if lib.is_integer(loc):
-                        new_index = index[loc : loc + 1]
-                    else:
-                        new_index = index[loc]
+            loc, new_index = index._get_loc_level(key, level=0)
+            if not drop_level:
+                if lib.is_integer(loc):
+                    new_index = index[loc : loc + 1]
+                else:
+                    new_index = index[loc]
         else:
             loc = index.get_loc(key)
 

pandas/core/indexes/multi.py

@@ -2988,6 +2988,7 @@ def maybe_mi_droplevels(indexer, levels):
         if isinstance(key, tuple) and level == 0:
 
             try:
+                # Check if this tuple is a single key in our first level
                 if key in self.levels[0]:
                     indexer = self._get_level_indexer(key, level=level)
                     new_index = maybe_mi_droplevels(indexer, [0])
@@ -3021,19 +3022,25 @@ def maybe_mi_droplevels(indexer, levels):
                 indexer = None
                 for i, k in enumerate(key):
                     if not isinstance(k, slice):
-                        k = self._get_level_indexer(k, level=i)
-                        if isinstance(k, slice):
-                            # everything
-                            if k.start == 0 and k.stop == len(self):
-                                k = slice(None, None)
+                        loc_level = self._get_level_indexer(k, level=i)
+                        if isinstance(loc_level, slice):
+                            if com.is_null_slice(loc_level) or com.is_full_slice(
+                                loc_level, len(self)
+                            ):
+                                # everything
+                                continue
+                            else:
+                                raise TypeError(
+                                    f"Expected label or tuple of labels, got {key}"
+                                )
                         else:
-                            k_index = k
+                            k_index = loc_level
 
-                    if isinstance(k, slice):
-                        if k == slice(None, None):
-                            continue
-                        else:
-                            raise TypeError(key)
+                    elif com.is_null_slice(k):
+                        # taking everything, does not affect `indexer` below
+                        continue
+                    else:
+                        raise TypeError(f"Expected label or tuple of labels, got {key}")
 
                     if indexer is None:
                         indexer = k_index