How to use classes of pythonPlugin? always compile failed, say can't find package

You must set/add Python dependencies as described here first: https://plugins.jetbrains.com/docs/intellij/pycharm.html

Hi Yann Cebron,

Thanks for your help. I have followed the steps to set it up, but still fail. This is my "build.gradle" and "plugin.xml":

Is there anything wrong?

build.gradle

plugins {
    id 'org.jetbrains.intellij' version '1.4.0'
    id 'java'
}

group 'com.sannmizu.example'
version '1.0-SNAPSHOT'

sourceCompatibility = 11

repositories {
    mavenCentral()
}

dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
}

// See https://github.com/JetBrains/gradle-intellij-plugin/
intellij {
    version = '2021.3.2'
    type = 'PC'
    downloadSources = false
    sandboxDir = 'D:\\Project\\Sandbox'
}

patchPluginXml {
    changeNotes = """
      Add change notes here.<br>
      <em>most HTML tags may be used</em>"""
}

test {
    useJUnitPlatform()
}

plugin.xml

<idea-plugin>
    <id>com.sannmizu.example.StepPlugin</id>
    <name>Step Tc Tp</name>
    <vendor email="sannmizu@qq.com">Sannmizu</vendor>

    <description>
        .tc .tp文件的简单转到插件，能够点击函数直接跳转，提供了函数名补全，路径补全
    </description>

    <!-- please see https://plugins.jetbrains.com/docs/intellij/plugin-compatibility.html
         on how to target different products -->
    <depends>com.intellij.modules.platform</depends>
    <depends>com.intellij.modules.xml</depends>
    <depends>com.intellij.modules.lang</depends>
    <depends>com.intellij.modules.python</depends>


    <extensions defaultExtensionNs="com.intellij">
        <!-- Add your extensions here -->
        <fileType name="TestPoint" implementationClass="com.sannmizu.example.step.TestPointFileType" fieldName="INSTANCE" language="TestPoint" extensions="tp"/>
        <fileType name="TestCase" implementationClass="com.sannmizu.example.step.TestCaseFileType" fieldName="INSTANCE" language="TestCase" extensions="tc"/>
        <psi.referenceContributor implementation="com.sannmizu.example.step.TestCaseReferenceContributor"/>
    </extensions>

    <actions>
        <!-- Add your actions here -->
    </actions>
</idea-plugin>

I find that add the dependency to the "PythonCore" can resovle it:

https://plugins.jetbrains.com/docs/intellij/plugin-dependencies.html#3-dependency-declaration-in-pluginxml 

Dose this complict with the description "No specific declaration is needed to use PY or PC APIs." ?