Bug: Trying to add a table with an absent style creates the table but does not return it #1631

Consider this snippet:

        # If the user has passed in a template with proper styles, we
        # can use the expected table style
        try:
            table = self.doc.add_table(rows = 1, cols = 5, style = "RDW banded table")

        except:
            table = self.doc.add_table(rows = 1, cols = 5)

        ...
        table.rows[0].cells[0].text = "Unit"
        ...

For context, I did this because it was less effort than interrogating the document for the style, so I fully admit I was cheating!

If the style "RDW banded table" is not present in the document (no template passed at Document creation), a KeyError exception is raised. I then catch this and create the table without the style.

The style is not checked in Document.add_table() - the table is created and then its style is set. The exception is then raised when the style is found to be missing, but Document.add_table() does not catch it and remove the table. Because the exception is not handled, it is thrown out to my own calling function; Document.add_table() does not return and I do not have a handle on the table (i.e. the table variable).

I then add the table a second time. At least in LibreOffice Writer, this results in the tables being combined from the GUI point of view, so when I come to populate the first row, the texts are put in the second row of the table from the GUI point of view.

Recommended solutions

1. Check a style in Document.add_table() before creating the table so that either the exception is thrown out to the caller before a table is created or the table is created anyway, but is returned to the caller.
2. Create the table in Document.add_table(), but handle the exception when the style is set by deleting the table.