<img src="/img/tutorial/dependencies/image01.png">

## Simple usage { #simple-usage }

If you look at it, *path operation functions* are declared to be used whenever a *path* and *operation* matches, and then **FastAPI** takes care of calling the function with the correct parameters, extracting the data from the request.

Actually, all (or most) of the web frameworks work in this same way.

Similarly, you cannot redefine a path operation:

{* ../../docs_src/path_params/tutorial003b_py39.py hl[6,11] *}

The first one will always be used since the path matches first.

## Predefined values { #predefined-values }

    //                                                                        Small Helper
    //                                                                        ============
    /**
     * Verify that the CRUD mode matches the expected mode.
     *
     * @param crudMode the actual CRUD mode
     * @param expectedMode the expected CRUD mode
     * @param dictId the dictionary ID for error redirection
     */

            final Pattern pattern = Pattern.compile(regex);
            System.getProperties()
                    .keySet()
                    .stream()
                    .filter(k -> k != null && pattern.matcher(k.toString()).matches())
                    .forEach(k -> addSystemProperty(cmdList, k.toString(), null, null));
        }
    }

    /**
     * Deletes the specified temporary directory.

        // Verify signature is zeroed out (16 bytes of zeros)
        for (int i = 4; i < 20; i++) {
            assertEquals(0, aad[i], "Signature bytes should be zero in AAD");
        }

        // Verify nonce matches at position 20
        for (int i = 0; i < 16; i++) {
            assertEquals(testNonce[i], aad[20 + i], "Nonce should match at position " + (20 + i));
        }
    }

    @Test

      allJvmArgs = allJvmArgs.filter { !it.startsWith("--add-opens") }
    }
    if (name.matches("test.*UnitTest".toRegex()) && javaLauncher.get().metadata.languageVersion.asInt() < 17) {
      // Work around robolectric requirements and limitations
      // https://github.com/robolectric/robolectric/issues/10419

            if (artifact.isSnapshot()) {
                Matcher matcher = Artifact.VERSION_FILE_PATTERN.matcher(artifact.getVersion());
                if (matcher.matches()) {
                    Snapshot snapshot = new Snapshot();
                    snapshot.setTimestamp(matcher.group(2));
                    try {
                        snapshot.setBuildNumber(Integer.parseInt(matcher.group(3)));

import assertk.assertThat
import assertk.assertions.isEqualTo
import assertk.assertions.isLessThan
import assertk.assertions.isLessThanOrEqualTo
import assertk.assertions.isSameInstanceAs
import assertk.assertions.matches
import java.net.UnknownHostException
import mockwebserver3.MockResponse
import mockwebserver3.MockWebServer
import mockwebserver3.junit5.StartStop
import okhttp3.HttpUrl
import okhttp3.Interceptor

			continue
		}
		if !meta.IsValid() {
			inconsistent++
			continue
		}
		if meta.XLV1 != fi.XLV1 {
			inconsistent++
			continue
		}
		// check if erasure distribution order matches the index
		// position if this is not correct we discard the disk
		// and move to collect others
		if distribution[i] != meta.Erasure.Index {
			inconsistent++ // keep track of inconsistent entries
			continue
		}

                    int startOffset = text.indexOf(word, offset);
                    int endOffset = startOffset + word.length();

                    // Handle decimal numbers
                    if (word.matches("\\d+") && startOffset > 0 && text.charAt(startOffset - 1) == '.') {
                        continue;
                    }