Creating the dependency between Custom Picklist and Global Picklist using the MetadataService in Apex Salesforce

Dependency between Custom Picklist and Global Picklist using the MetadataService

public static void createPicklistDependencyWithGlobalPicklist() {

    // Creating each controlling value and the dependent value - STARTS
    MetadataService.valueSettings controllingAndDependentValueSetting = new MetadataService.valueSettings();
    controllingAndDependentValueSetting.controllingFieldValue = new List<String>{
        'None'
    };
    controllingAndDependentValueSetting.valueName = 'test1';

    List<MetadataService.valueSettings> controllingAndDependentValueSettings = new List<MetadataService.valueSettings>{
        controllingAndDependentValueSetting
    };
    // Creating each controlling value and the dependent value - ENDS

    // Valuset definition - STARTS
    // pick list value
    metadataservice.CustomValue firstPicklistValue = new metadataservice.CustomValue();
    firstPicklistValue.fullName = 'None';
    firstPicklistValue.label = 'None';
    firstPicklistValue.default_x = false;

    MetadataService.ValueSetValuesDefinition valueSetDefinition = new MetadataService.ValueSetValuesDefinition();
    valueSetDefinition.sorted = false;
    valueSetDefinition.value = new List<metadataservice.CustomValue>{
        firstPicklistValue
    };
    // Valuset definition - ENDS

    // Picklist ValueSet - STARTS
    MetadataService.ValueSet picklistValueSet = new MetadataService.ValueSet();
    picklistValueSet.valueSetName = 'Remove'; // This is the global value set name
    picklistValueSet.valueSettings = controllingAndDependentValueSettings;
    picklistValueSet.controllingField = 'Remove_Picklist__c'; // Controlling Field including the object api name (for the global picklist this should not be there)
    picklistValueSet.restricted = true;
    // picklistValueSet.valueSetDefinition = valueSetDefinition; // This should not be added for the global picklst
    // Picklist ValueSet - ENDS

    // Custom Field - STARTS
    MetadataService.CustomField customField = new MetadataService.CustomField();
    customField.fullName = 'Account.Global_Remove_Picklist__c'; // Dependent Field including the object name
    customField.type_x = 'Picklist';
    customField.label = 'Global Remove Picklist';
    customField.valueSet  = picklistValueSet;
    // Custom Field - ENDS

    // Deploying Custom Field - STARTS
    MetadataService.MetadataPort service = createService();

    List<MetadataService.SaveResult> saveResult = new List<MetadataService.SaveResult> {
        service.updateMetadata(
            new MetadataService.Metadata[] { customField }
        )[0]
    };

    // Update Custom Field
    handleSaveResults(
        saveResult
    );  
    // Deploying Custom Field - ENDS

}