docs: def hash_file(filename):
     """"This function returns the SHA-1 hash
     of the file passed into it"""
  
     # make a hash object
     h = hashlib.sha1()
  
     # open file for reading in binary mode
     with open(filename,'rb') as file:
  
         # loop till the end of the file
         chunk = 0
         while chunk != b'':
             # read only 1024 bytes at a time
             chunk = file.read(1024)
             h.update(chunk)
  
     # return the hex representation of digest
     return h.hexdigest()