Check for empty output before writing to disk
Created by: raghuramdr
Line 93 in the file downloader.py checks if the file size is 0 after writing to disk. This is
- A waste of time if the file is indeed empty, because it is unnecessarily written to disk
- It is a bug, because, when for a new drug, the FASTA file existence is checked, the condition is evaluated to True, since the file would be on disk, even though it is empty