docs: def read_buf(self):
          """Read database file"""
  
          with open(self.filepath, 'rb') as handler:
              try:
                  buf = handler.read()
                  
                  # There should be a header at least
                  if len(buf) < 124:
                      raise KPError('Unexpected file size. It should be more or'
                                    'equal 124 bytes but it is '
                                    '{0}!'.format(len(buf)))
              except:
                  raise
          return buf