Attempt to extract a frame for displaying a product called `name` from the `debugDisplay` variable.
Per the above, an instance of `Info` can return an arbitrary object (or nothing) as its `display`
attribute. It is convenient -- though not required -- that it be a dictionary mapping data products
to frame numbers, as shown in the `lsstDebug.Info` example. Given such a dictionary, this function
extracts and returns the appropriate frame number. If `debugDisplay` is not a collection, or if
`name` is not found within it, we return `None`.
@param[in] debugDisplay The contents of lsstDebug.Info(__name__).display.
@param[in] name The name of the data product to be displayed.
@returns A frame number
Definition at line 66 of file lsstDebug.py.