doctest fix for #42670

Author: KrishnaSai2020

pandas/io/formats/format.py

@@ -1952,13 +1952,13 @@ def __init__(self, accuracy: int | None = None, use_eng_prefix: bool = False):
         self.accuracy = accuracy
         self.use_eng_prefix = use_eng_prefix
 
-    def __call__(self, num: int | float) -> int:
+    def __call__(self, num: int | float) ->str:
         """
         Formats a number in engineering notation, appending a letter
         representing the power of 1000 of the original number. Some examples:
         >>> format_eng = EngFormatter()
         >>> format_eng(0)       # for self.accuracy = 0
-        '0'
+        ' 0'
 
         >>> format_eng(1000000) # for self.accuracy = 1,
                                 #     self.use_eng_prefix = True
@@ -1984,7 +1984,7 @@ def __call__(self, num: int | float) -> int:
 
         sign = 1
         if dnum == 0:
-            formatted = 0
+            formatted = ' 0'
             return formatted
 
         if dnum < 0:  # pragma: no cover