Adds a text header to the display with the specified level.
str
The text to display in the header.
int
The level of the header, which corresponds to the html header levels, such as <h1>, <h2>, ...
1
bool
Whether or not the header will expand to fill the width of the entire notebook page, or be constrained by automatic maximum page width. The default value of False lines the header up with text displays.
False