human
Solve the following python programming problem given the following code:
@ cli.command ('build') 
@ click.option ('-O', '--output-path', type = click.Path (), default = None, help = 'The output path.') 
@ click.option ('--watch', is_flag = True, help = 'If this is enabled the build process goes into an automatic loop where it watches the file system for changes and rebuilds.') 
@ click.option ('--prune/--no-prune', default = True, help = 'Controls if old artifacts should be pruned.  This is the default.') 
@ click.option ('-v', '--verbose', 'verbosity', count = True, help = 'Increases the verbosity of the logging.') 
@ click.option ('--source-info-only', is_flag = True, help = 'Instead of building only updates the source infos.  The source info is used by the web admin panel to quickly find information about the source files (for instance jump to files).') 
@ buildflag 
@ click.option ('--profile', is_flag = True, help = 'Enable build profiler.') 
@ pass_context 
def build_cmd(ctx, output_path, watch, prune, verbosity, source_info_only, profile, build_flags) : 
    'Builds the entire project into the final artifacts.

    The default behavior is to build the project into the default build
    output path which can be discovered with the `project-info` command
    but an alternative output folder can be provided with the `--output-path`
    option.

    The default behavior is to perform a build followed by a pruning step
    which removes no longer referenced artifacts from the output folder.
    Lektor will only build the files that require rebuilding if the output
    folder is reused.

    To enforce a clean build you have to issue a `clean` command first.

    If the build fails the exit code will be `1` otherwise `0`.  This can be
    used by external scripts to only deploy on successful build for instance.
    ' 
    from lektor.builder import Builder 
    from lektor.reporter import CliReporter 
    if (output_path is None) : 
        output_path = ctx.get_default_output_path () 
ctx.load_plugins () 
    env = ctx.get_env () 
    def _build() : 
        builder = Builder...

    
    

    Fix the buggy line: for (ts, _, _) in watch (_build) :
assistant
#Here is Python program to find information about the source files (for instance jump to files).

for (ts, _, _) in watch (env) :