Are optional dependencies really optional? about spidermon HOT 6 CLOSED

Traceback (most recent call last):
  File "/myproject/env/bin/scrapy", line 11, in <module>
    sys.exit(execute())
  File "/myproject/env/lib/python3.6/site-packages/scrapy/cmdline.py", line 150, in execute
    _run_print_help(parser, _run_command, cmd, args, opts)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/cmdline.py", line 90, in _run_print_help
    func(*a, **kw)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/cmdline.py", line 157, in _run_command
    cmd.run(args, opts)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/commands/crawl.py", line 57, in run
    self.crawler_process.crawl(spname, **opts.spargs)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/crawler.py", line 170, in crawl
    crawler = self.create_crawler(crawler_or_spidercls)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/crawler.py", line 198, in create_crawler
    return self._create_crawler(crawler_or_spidercls)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/crawler.py", line 203, in _create_crawler
    return Crawler(spidercls, self.settings)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/crawler.py", line 55, in __init__
    self.extensions = ExtensionManager.from_crawler(self)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/middleware.py", line 58, in from_crawler
    return cls.from_settings(crawler.settings, crawler)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/middleware.py", line 34, in from_settings
    mwcls = load_object(clspath)
  File "/myproject/env/lib/python3.6/site-packages/scrapy/utils/misc.py", line 44, in load_object
    mod = import_module(module)
  File "/usr/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/myproject/env/lib/python3.6/site-packages/spidermon/contrib/scrapy/extensions.py", line 11, in <module>
    from spidermon.python import factory
  File "/myproject/env/lib/python3.6/site-packages/spidermon/python/__init__.py", line 3, in <module>
    from . import factory
  File "/myproject/env/lib/python3.6/site-packages/spidermon/python/factory.py", line 3, in <module>
    from jsonschema import validate
ModuleNotFoundError: No module named 'jsonschema'