DefaultKVS[subSys] = kvs
	}
}

// HelpSubSysMap - help for all individual KVS for each sub-systems
// also carries a special empty sub-system which dumps
// help for each sub-system key.
var HelpSubSysMap = map[string]HelpKVS{}

// RegisterHelpSubSys - this function saves
// input help KVS for each sub-system globally,
// this function should be called only once
// preferably in during `init()`.

	globalBucketMonitor = bandwidth.NewMonitor(ctx, uint64(totalNodeCount()))

	// Create a new config system.
	globalConfigSys = NewConfigSys()

	// Create new IAM system.
	globalIAMSys = NewIAMSys()

	// Create new policy system.
	globalPolicySys = NewPolicySys()

	// Create new lifecycle system.
	globalLifecycleSys = NewLifecycleSys()

	// Create new bucket encryption subsystem

It's relatively tightly coupled with relational databases (like MySQL or PostgreSQL), so, having a NoSQL database (like Couchbase, MongoDB, Cassandra, etc) as the main store engine is not very easy.

The simplicity of the dependency injection system makes **FastAPI** compatible with:

* all the relational databases
* NoSQL databases
* external packages
* external APIs
* authentication and authorization systems
* API usage monitoring systems
* response data injection systems
* etc.

## Simple and Powerful

		if !ok {
			return Help{}, config.Errorf("unknown sub-system %s", subSys)
		}
	}

	h, ok := config.HelpSubSysMap[subSys]
	if !ok {
		return Help{}, config.Errorf("unknown sub-system %s", subSys)
	}
	if key != "" {
		value, ok := h.Lookup(key)
		if !ok {
			return Help{}, config.Errorf("unknown key %s for sub-system %s",
				key, subSys)
		}
		h = config.HelpKVS{value}
	}

      means any form of electronic, verbal, or written communication sent
      to the Licensor or its representatives, including but not limited to
      communication on electronic mailing lists, source code control systems,
      and issue tracking systems that are managed by, or on behalf of, the
      Licensor for the purpose of discussing and improving the Work, but
      excluding communication that is conspicuously marked or otherwise

      means any form of electronic, verbal, or written communication sent
      to the Licensor or its representatives, including but not limited to
      communication on electronic mailing lists, source code control systems,
      and issue tracking systems that are managed by, or on behalf of, the
      Licensor for the purpose of discussing and improving the Work, but
      excluding communication that is conspicuously marked or otherwise

      means any form of electronic, verbal, or written communication sent
      to the Licensor or its representatives, including but not limited to
      communication on electronic mailing lists, source code control systems,
      and issue tracking systems that are managed by, or on behalf of, the
      Licensor for the purpose of discussing and improving the Work, but
      excluding communication that is conspicuously marked or otherwise

	"runtime"
	"strconv"
	"strings"
	"unicode"
)

var gormSourceDir string

func init() {
	_, file, _, _ := runtime.Caller(0)
	// compatible solution to get gorm source directory with various operating systems
	gormSourceDir = sourceDir(file)
}

func sourceDir(file string) string {
	dir := filepath.Dir(file)
	dir = filepath.Dir(dir)

	s := filepath.Dir(dir)
	if filepath.Base(s) != "gorm.io" {
		s = dir
	}

It can be used by the frontend team (that can also be yourself).

It can be used by third party applications and systems.

And it can also be used by yourself, to debug, check and test the same application.

## The `password` flow

Now let's go back a bit and understand what is all that.