code: def begin_write(self, content_type=None):
          
          assert not self.is_collection
          self._check_write_access()
          mode = "wb"
          # GC issue 57: always store as binary
          #        if contentType and contentType.startswith("text"):
          #            mode = "w"
          return open(self.absFilePath, mode, BUFFER_SIZE)
docs: Open content as a stream for writing.
  
          See DAVResource.begin_write()