diff --git a/python/damask/_grid.py b/python/damask/_grid.py
index f7acfe5aa..4e82a4180 100644
--- a/python/damask/_grid.py
+++ b/python/damask/_grid.py
@@ -50,15 +50,16 @@ class Grid:
             Coordinates of grid origin in meter. Defaults to [0.0,0.0,0.0].
         initial_conditions : dictionary, optional
             Labels and values of the inital conditions at each material point.
-        comments : (list of) str, optional
-            Comments, e.g. history of operations.
+        comments : str or iterable of str, optional
+            Additional, human-readable information, e.g. history of operations.
 
         """
         self.material = material
         self.size = size                                                        # type: ignore
         self.origin = origin                                                    # type: ignore
         self.initial_conditions = {} if initial_conditions is None else initial_conditions
-        self.comments = [] if comments is None else comments                    # type: ignore
+        comments_ = [comments] if isinstance(comments,str) else comments
+        self.comments = [] if comments_ is None else [str(c) for c in comments_]
 
     def __repr__(self) -> str:
         """Give short human-readable summary."""
diff --git a/python/damask/_table.py b/python/damask/_table.py
index 293f8fb1a..daba4ab95 100644
--- a/python/damask/_table.py
+++ b/python/damask/_table.py
@@ -14,7 +14,7 @@ class Table:
     def __init__(self,
                  shapes: dict,
                  data: np.ndarray,
-                 comments: Union[str, Iterable] = None):
+                 comments: Union[str, Iterable[str]] = None):
         """
         New spreadsheet.
 
@@ -30,7 +30,7 @@ class Table:
 
         """
         comments_ = [comments] if isinstance(comments,str) else comments
-        self.comments = [] if comments_ is None else [c for c in comments_]
+        self.comments = [] if comments_ is None else [str(c) for c in comments_]
         self.shapes = { k:(v,) if isinstance(v,(np.int64,np.int32,int)) else v for k,v in shapes.items() }
         self.data = pd.DataFrame(data=data)
         self._relabel('uniform')
diff --git a/python/damask/_vtk.py b/python/damask/_vtk.py
index 17d8afa53..c41470638 100644
--- a/python/damask/_vtk.py
+++ b/python/damask/_vtk.py
@@ -103,7 +103,7 @@ class VTK:
 
         Parameters
         ----------
-        comments : str or list of str
+        comments : str or sequence of str
             Comments.
 
         """