Treepoem barcode generator unable to find ghostscript
You are installing on Windows, the Windows binary differs in name from the Linux binaries and indeed differs depending whether  you installed the 64 or 32-bit version.
On Linux (and MacOS) the Ghostscript binary is called 'gs', on Windows its 'gswin32' or 'gswin64' or 'gswin32c' or 'gswin64c' depending on whether you want the 32 or 64 bit version, and the command line or windowed executable.
My guess is that your script is looking for simply 'gs' and is probably expecting the path to be in the $PATH environment variable, its not clear to me what its expecting.
You could probably 'fix' this by making sure the installation path is in the $PATH environment variable and copying the executable to 'gs.exe' in that directory.
Other than that you'll need someone who can tell you what the script is looking for. Quite possibly you could just grep it.
I'm trying to generate a pdf417 barcode in python using treepoem but pycharm keeps giving me the following error:
Traceback (most recent call last):
File "C:/Users/./Documents/barcodes.py", line 175, in 
    image = generate_barcode(barcode_type="pdf417",data=barcode, options=dict(eclevel=5, rows=27, columns=12))
  File "C:\Users.\AppData\Local\Programs\Python\Python36-32\lib\site-packages\treepoem__init__.py", line 141, in generate_barcode
    bbox_lines = _get_bbox(code)
  File "C:\Users.\AppData\Local\Programs\Python\Python36-32\lib\site-packages\treepoem__init__.py", line 81, in _get_bbox
    ghostscript = _get_ghostscript_binary()
  File "C:\Users.\AppData\Local\Programs\Python\Python36-32\lib\site-packages\treepoem__init__.py", line 108, in _get_ghostscript_binary
    'Cannot determine path to ghostscript, is it installed?'
treepoem.TreepoemError: Cannot determine path to ghostscript, is it installed?
I've tried to install ghostcript, using both the .exe I found online and using pip install ghostscript (successfully completed the first time, and now tells me the requirement is satisfied), yet I still keep getting this error. Any ideas on how to fix it?