Cannot add to existing webdir when it ends with `/`

When passing the existing webdir as --existing_webdir /home/sylvia.biscoveanu/public_html/O3/S190704o/, I get the error:

Traceback (most recent call last):
  File "/home/sylvia.biscoveanu/virtualenvs/pesummary/bin/summarypages", line 11, in <module>
    load_entry_point('pesummary==0.1.7', 'console_scripts', 'summarypages')()
  File "/home/sylvia.biscoveanu/virtualenvs/pesummary/lib/python3.6/site-packages/pesummary-0.1.7-py3.6.egg/cli/summarypages.py", line 875, in main
    args = func["input"](opts)
  File "/home/sylvia.biscoveanu/virtualenvs/pesummary/lib/python3.6/site-packages/pesummary-0.1.7-py3.6.egg/pesummary/gw/inputs.py", line 82, in __init__
    self.webdir = opts.webdir
  File "/home/sylvia.biscoveanu/virtualenvs/pesummary/lib/python3.6/site-packages/pesummary-0.1.7-py3.6.egg/pesummary/core/inputs.py", line 151, in webdir
    raise Exception("Please give the base directory of an "
Exception: Please give the base directory of an existing output

However, when I remove the last slash from the existing webdir, things run fine. The issue is that in input.py, it was looking for /home/sylvia.biscoveanu/public_html/O3/S190704o//home.html in a list of entries that only had a single slash.