diff --git a/ignite/utils.py b/ignite/utils.py
index 0de0f5737100..7961130108e8 100644
--- a/ignite/utils.py
+++ b/ignite/utils.py
@@ -128,21 +128,54 @@ def flatten_to_str(data: Any) -> List[str]:
         structure.
 
     Examples:
-        >>> flatten_to_str(42)
-        ['42.0000']
+        Use the function to flatten and format various data structures.
 
-        >>> flatten_to_str([1, 2.34567, 3])
-        ['1.0000, 2.3457, 3.0000']
+        .. testsetup:: *
 
-        >>> flatten_to_str({'a': 1, 'b': [2, 3], 'c': None})
-        ['a: 1.0000', 'b: 2.0000, 3.0000', 'c: ']
+            from ignite.utils import flatten_to_str
+            import torch
 
-        >>> flatten_to_str(torch.tensor([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]))
-        ['[1.0000, 2.0000, 3.0000, 4.0000, 5.0000, 6.0000, 7.0000, 8.0000, 9.0000, 10.0000, ...]']
+        .. testcode::
 
-        >>> flatten_to_str({'tensor': torch.tensor([[1, 2], [3, 4]])})
-        ['tensor: Shape: torch.Size([2, 2])']
+            flatten_to_str(42)
+
+        .. testoutput::
+
+            ['42.0000']
+
+        .. testcode::
+
+            flatten_to_str([1, 2.34567, 3])
+
+        .. testoutput::
+
+            ['1.0000, 2.3457, 3.0000']
+
+        .. testcode::
+
+            flatten_to_str({'a': 1, 'b': [2, 3], 'c': None})
+
+        .. testoutput::
+
+            ['a: 1.0000', 'b: 2.0000, 3.0000', 'c: ']
+
+        .. testcode::
+
+            flatten_to_str(torch.tensor([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]))
+
+        .. testoutput::
+
+            ['[1.0000, 2.0000, 3.0000, 4.0000, 5.0000, 6.0000, 7.0000, 8.0000, 9.0000, 10.0000, ...]']
+
+        .. testcode::
+
+            flatten_to_str({'tensor': torch.tensor([[1, 2], [3, 4]])})
+
+        .. testoutput::
+
+            ['tensor: Shape: torch.Size([2, 2])']
     """
+
     formatted_items: List[str] = []
 
     def format_item(item: Any, prefix: str = "") -> Optional[str]: