I have the below columns in my dataframe ABC.

• userLabel
• userLabel

Both are same name

I need to club both and make it as a single column userLabel.
For example if i have below data

userLabel = ['a', '', 3, '', 'b']
userLabel = ['', '2', '', '4', '']

I need like below

userLabel = ['a', 2, 3, 4, 'b']

I tried the below code but didn’t work

   ABC['userLabel'] = ABC['userLabel'].fillna(ABC['userLabel'])