* </ul>
     *
     * @param relPath is the path of the requested model source relative to this model source POM.
     * @return related model source or <code>null</code> if no such model source.
     */
    ModelSource2 getRelatedSource(String relPath);

    /**
     * Returns location of the POM, never <code>null</code>.
     */
    URI getLocationURI();

And Pydantic's `Field` returns an instance of `FieldInfo` as well.

`Body` also returns objects of a subclass of `FieldInfo` directly. And there are others you will see later that are subclasses of the `Body` class.

Remember that when you import `Query`, `Path`, and others from `fastapi`, those are actually functions that return special classes.

///

/// tip

### Use cases: external service { #use-cases-external-service }

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

        this.element = element;
        this.index = index;
    }

    /**
     * Returns the element.
     *
     * @return the element
     */
    public T getElement() {
        return element;
    }

    /**
     * Returns the index.
     *
     * @return the index
     */
    public int getIndex() {
        return index;
    }

        assertNull(delegatingConfig.getRandom(), "Should return null when delegate returns null");
        assertNull(delegatingConfig.getLocalAddr(), "Should return null when delegate returns null");
        assertNull(delegatingConfig.getNetbiosHostname(), "Should return null when delegate returns null");
        assertNull(delegatingConfig.getResolveOrder(), "Should return null when delegate returns null");

// or under <filter><and></and></filter>. This method returns the prefix from the
// location where it is available.
func (r Rule) GetPrefix() string {
	if p := r.Prefix.String(); p != "" {
		return p
	}
	if p := r.Filter.Prefix.String(); p != "" {
		return p
	}
	if p := r.Filter.And.Prefix.String(); p != "" {
		return p
	}
	return ""
}

	}
	return ""
}

// Validate - validates the rule element
func (r Rule) Validate(bucket string, sameTarget bool) error {
	if err := r.validateID(); err != nil {
		return err
	}
	if err := r.validateStatus(); err != nil {
		return err
	}
	if err := r.validateFilter(); err != nil {
		return err
	}
	if err := r.DeleteMarkerReplication.Validate(); err != nil {
		return err
	}

        if (maxLength != null && maxLength >= 0L) {
            return maxLength;
        }
        return defaultMaxLength;
    }

    /**
     * Returns the default maximum content length.
     * @return The default maximum content length in bytes.
     */
    public long getDefaultMaxLength() {
        return defaultMaxLength;
    }

    /**
     * Sets the default maximum content length.

        assertArgumentNotNull("reader", reader);
        return iterable(new BufferedReader(reader));
    }

    /**
     * Returns an {@link Iterable} that wraps a {@link LineIterator} for use in enhanced for-loops.
     *
     * @param reader
     *            The {@link BufferedReader} to read strings from. Must not be {@literal null}.
     * @return An {@link Iterable} that wraps a {@link LineIterator}.
     */

      )
    ) {
      return false
    }

    return true
  }

  override fun equals(other: Any?): Boolean {
    if (other !is ConnectionSpec) return false
    if (other === this) return true

    if (this.isTls != other.isTls) return false

    if (isTls) {
      if (!Arrays.equals(this.cipherSuitesAsString, other.cipherSuitesAsString)) return false