Default string to be treated as missing value in a series.
Hi, this is more of a question than an issue.
I wanted to use default string as a representation for missing values for my project. Is there a way to incorporate inside my pandas lib or implementing it in the project is the only way to do?
For example :  I want to use '?' to show that my some value in my datetime type series is missing, instead of pd.NaT. Now pd.NaT will respond to addition operation but '?' won't. Can I make '?' to be treated as missing value and if yes is there a way to do inside pandas? This should also mean that <series> is retained as datetime type and not object.