Returns:
         A new diagnostic context.
  Return type:
     *DiagnosticContext*

pretty_print(verbose=False, level=Level.ERROR)
  Pretty prints all diagnostics in the diagnostic contexts.

  Parameters:
     * **verbose** (*bool*) -- Whether to print the diagnostics in
       verbose mode. See Diagnostic.pretty_print.

     * **level** (*Level*) -- The minimum level of diagnostics to
       print.
