iterating through list of excel files; how to skip opening file if excel file lacks sheet_name criteria
As I thought about my question while working on my question in stackoverflow and reading not on point questions, an answer came to me.  This works and seems Pythonic to me:
...
for file in files_to_process:
    try:
        df = pd.read_excel(file, usecols=colNames, sheet_name='Unbilled', index=0, header=4)
    except:
        print('The following file lacks sheet_name=Unbilled: ', file)
        pass
...
I have a group of excel files in a directory.  I put the list of file names in a list and iterate over them to concatenate certain columns into a single file.  Periodically, one of the files does not have the proper sheet name, and the my notebook throws an error.  
I get it that I could first open the file another way and then query the file to see if it contains the sheet_name.  I just want to be Pythonic: I am asking if file lacks sheet_name='Unbilled' go to next file. 
...
for file in files_to_process:
    df = pd.read_excel(file, usecols=colNames, sheet_name='Unbilled', index=0, header=4)
...
I am doing this in a Jupyter notebook, just FYI