How to unzip Sentinel-5P file

I can’t unzip a .zip file downloaded from Copernicus Open Access Hub. I retrieve the file and i try to unzip it using the following Python script:

from sentinelsat.sentinel import SentinelAPI
import zipfile

user = 's5pguest' 
password = 's5pguest' 

api = SentinelAPI(user, password, '')"cb078cce-ed6e-46a7-a614-e13830b2a74a")

# The file is succesfully downloaded
zip_ref = zipfile.ZipFile("", 'r')

The file is succesfully downloaded, but when it tries to unzip i get:

BadZipFile                                Traceback (most recent call last)
<ipython-input-3-45c213a35459> in <module>
---> 11 zip_ref = zipfile.ZipFile("", 'r')
     12 zip_ref.extractall()
     13 zip_ref.close()

~/anaconda3/lib/python3.6/ in __init__(self, file, mode, compression, allowZip64)
   1129         try:
   1130             if mode == 'r':
-> 1131                 self._RealGetContents()
   1132             elif mode in ('w', 'x'):
   1133                 # set the modified flag so central directory gets written

~/anaconda3/lib/python3.6/ in _RealGetContents(self)
   1196             raise BadZipFile("File is not a zip file")
   1197         if not endrec:
-> 1198             raise BadZipFile("File is not a zip file")
   1199         if self.debug > 1:
   1200             print(endrec)

BadZipFile: File is not a zip file

If i try to unzip this file from the terminal with unzip i get:

End-of-central-directory signature not found.  Either this file is not
  a zipfile, or it constitutes one disk of a multi-part archive.  In the
  latter case the central directory and zipfile comment will be found on
  the last disk(s) of this archive.
unzip:  cannot find zipfile directory in one of or, and cannot find, period.

If i try with 7zip i get:

7-Zip [64] 9.20  Copyright (c) 1999-2010 Igor Pavlov  2010-11-18
p7zip Version 9.20 (locale=it_IT.UTF-8,Utf16=on,HugeFiles=on,4 CPUs)

Processing archive:

Error: Can not open file as archive

It seems like the file is corrupted, but if i try to download other files the error remains.
I also tried to change the name in a simpler one like “”, without success.
I’m stucked, any ideas?

PS: i’m following this tutorial