Fix type checks

Author: salva

pandas/io/excel/_base.py

@@ -827,10 +827,10 @@ def _parse_sheet(
             elif is_integer(skiprows):
                 ixmap = range(skiprows, len(data))
             elif is_list_like(skiprows):
-                skiprows = set(skiprows)
-                ixmap = [ix for ix, _ in enumerate(data) if ix not in skiprows]
+                skiprows_set = set(skiprows)
+                ixmap = list(ix for ix, _ in enumerate(data) if ix not in skiprows_set)
             elif callable(skiprows):
-                ixmap = [ix for ix, _ in enumerate(data) if not skiprows(ix)]
+                ixmap = list(ix for ix, _ in enumerate(data) if not skiprows(ix))
             else:
                 raise ValueError(
                     "skiprows must be an integer or a list of integers"
@@ -844,23 +844,24 @@ def _parse_sheet(
             elif isinstance(index_col, str):
                 index_col_set = set()
                 index_col_has_names = True
-            elif is_integer(index_col):
+            elif isinstance(index_col, int):
                 index_col_set = {index_col}
             elif is_list_like(index_col):
-                index_col_set = set(index_col)
+                index_col_set = set(cast(Sequence[int], index_col))
             else:
                 raise ValueError(
                     "index_col must be a string, an integer or a list of integers"
                 )
             has_index = len(index_col_set) > 0
             has_index_names = False
 
+            header_list: list[int]
             if header is None:
                 header_list = []
             elif is_integer(header):
                 header_list = [header]
             elif is_list_like(header):
-                header_list = header
+                header_list = cast(Sequence[int], header)
             else:
                 raise ValueError(
                     "header must be an integer or a list of integers"
@@ -889,15 +890,16 @@ def _parse_sheet(
 
                     # Forward fill and pull out names for MultiIndex column
                     control_row = [True] * len(data[0])
-                    for row in header:
+                    for row in header_list:
                         row1 = ixmap[row]
                         data[row1], control_row = fill_mi_header(data[row1],
                                                                  control_row)
 
                         if has_index:
                             header_name, _ = pop_header_name(data[row1],
                                                              index_col)
-                            header_names.append(header_name)
+                            if header_name:
+                                header_names.append(header_name)
 
                     # If there is a MultiIndex header and an index then
                     # there may also be a row containing just the index