Avoid Soql using Custom Metadata Type - Platform Developer I Certification Maintenance (Winter '22)

Code without getInstance - 

public class CountryCodeHelper {
  public static string getCountryCode(String country) {
    Country_Code__mdt countryCode = [
      SELECT Id, MasterLabel, Country_Code__c
      FROM Country_Code__mdt
      WHERE MasterLabel = :country
      LIMIT 1
    ];
 
    return countryCode.Country_Code__c;
  }
}

Efficient code by avoiding soql and leveraging getInstance method for custommetadata Types - 

Use the getInstance Method to Retrieve Custom Metadata

public class CountryCodeHelper {
  public static string getCountryCode(String country) {
   Country_Code__mdt countryCode= Country_Code__mdt.getInstance(country);
    return countryCode.Country_Code__c;
  }
} 

Platform Developer I Certification Maintenance Winter 22 Trailhead/Certification Maintenance link here