code: def get_code_snippet(self, filename, line_number, lines_of_context=5):
          
          secret_line_index = line_number - 1
          end_line = secret_line_index + lines_of_context + 1
  
          if secret_line_index <= lines_of_context:
              start_line = 0
              index_of_secret_in_output = secret_line_index
          else:
              start_line = secret_line_index - lines_of_context
              index_of_secret_in_output = lines_of_context
  
          return CodeSnippet(
              list(
                  itertools.islice(
                      self._get_lines_in_file(filename),
                      start_line,
                      end_line,
                  ),
              ),
              start_line,
              index_of_secret_in_output,
          )
docs: :type filename: str
  
          :type line_number: int
          :param line_number: line which you want to focus on
  
          :type lines_of_context: int
          :param lines_of_context: how many lines to display around the line you want
              to focus on.
  
          :rtype: CodeSnippet