But this way we can focus on how the **Dependency Injection** system works.

### Create a dependency, or "dependable"

Let's first focus on the dependency.

It is just a function that can take all the same parameters that a *path operation function* can take:

=== "Python 3.10+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="8-11"

        msgs.add("* An aggregator Mojo is already executing in parallel build,    *");
        msgs.add("* but aggregator Mojos require exclusive access to reactor to   *");
        msgs.add("* prevent race conditions. This mojo execution will be blocked  *");
        msgs.add("* until the aggregator work is done.                            *");
        msgs.add("*****************************************************************");

                </mxCell>

    return stringWriter.toString();
  }

  /**
   * Returns the stack trace of {@code throwable}, possibly providing slower iteration over the full
   * trace but faster iteration over parts of the trace. Here, "slower" and "faster" are defined in
   * comparison to the normal way to access the stack trace, {@link Throwable#getStackTrace()

    return stringWriter.toString();
  }

  /**
   * Returns the stack trace of {@code throwable}, possibly providing slower iteration over the full
   * trace but faster iteration over parts of the trace. Here, "slower" and "faster" are defined in
   * comparison to the normal way to access the stack trace, {@link Throwable#getStackTrace()

For this, use the Python standard module <a href="https://docs.python.org/3/library/secrets.html" class="external-link" target="_blank">`secrets`</a> to check the username and password.

`secrets.compare_digest()` needs to take `bytes` or a `str` that only contains ASCII characters (the ones in English), this means it wouldn't work with characters like `á`, as in `Sebastián`.

  latest version of some snapshot artifact. If m2 is offline, SCM operations
  cannot succeed; no artifact downloads can take place, regardless of whether
  they are snapshot versions; artifact deployment cannot take place; certain
  types of tests cannot be setup, since the container used to run them cannot be
  reached or started.

		Workload: podToWorkload(pod),
		Netns:    ns,
	}
	netns1 := p.UpsertPodCacheWithNetns(string(pod.UID), wl)
	netnsTaken := p.Take(string(pod.UID))
	if netns1 != netnsTaken {
		t.Fatalf("Expected the original Netns for the same uid, got %p and %p", netns1, ns)
	}
	if nil != p.Take(string(pod.UID)) {
		// expect nil because we already took it
		t.Fatalf("Expected nil Netns for the same uid twice")
	}
}

            bufferIndex += 4;

            if (numAces > 4096)
                throw new IOException( "Invalid SecurityDescriptor" );

            aces = new ACE[numAces];
            for (int i = 0; i < numAces; i++) {
                aces[i] = new ACE();
                bufferIndex += aces[i].decode(buffer, bufferIndex);
            }
        } else {
            aces = null;
        }

 *
 *  3. Attempt plans from prior connect attempts for this call. These occur as either follow-ups to
 *     failed connect attempts (such as trying the next [ConnectionSpec]), or as attempts that lost
 *     a race in fast follow-up.
 *
 *  4. If there's no existing connection, make a list of routes (which may require blocking DNS
 *     lookups) and attempt a new connection them. When failures occur, retries iterate the list of