Implementing requested changes.

Author: staudtMarius

src/main/java/edu/ie3/datamodel/io/source/csv/CsvThermalGridSource.java

@@ -5,7 +5,6 @@
 */
 package edu.ie3.datamodel.io.source.csv;
 
-import static edu.ie3.datamodel.utils.CollectionUtils.groupBy;
 import static java.util.Collections.emptySet;
 
 import edu.ie3.datamodel.exceptions.SourceException;
@@ -22,6 +21,7 @@
 import edu.ie3.datamodel.utils.Try;
 import java.nio.file.Path;
 import java.util.*;
+import java.util.stream.Collectors;
 
 /** Convenience class for cases where all used data comes from CSV sources */
 public class CsvThermalGridSource {
@@ -85,9 +85,11 @@ public static List<ThermalGrid> read(
       // filtered and thrown before
 
       Map<ThermalBusInput, Set<ThermalHouseInput>> houseInputs =
-          groupBy(houses.getOrThrow(), ThermalUnitInput::getThermalBus);
+          houses.getOrThrow().stream()
+              .collect(Collectors.groupingBy(ThermalUnitInput::getThermalBus, Collectors.toSet()));
       Map<ThermalBusInput, Set<ThermalStorageInput>> storageInputs =
-          groupBy(storages.getOrThrow(), ThermalUnitInput::getThermalBus);
+          storages.getOrThrow().stream()
+              .collect(Collectors.groupingBy(ThermalUnitInput::getThermalBus, Collectors.toSet()));
 
       return buses.values().stream()
           .map(

src/main/java/edu/ie3/datamodel/utils/CollectionUtils.java

@@ -8,7 +8,6 @@
 import static java.util.stream.Collectors.partitioningBy;
 
 import edu.ie3.datamodel.exceptions.FailureException;
-import edu.ie3.datamodel.exceptions.SourceException;
 import edu.ie3.datamodel.exceptions.TryException;
 import java.util.*;
 import java.util.function.Function;
@@ -594,7 +593,7 @@ public int hashCode() {
    */
   @FunctionalInterface
   public interface TrySupplier<T, E extends Exception> {
-    T get() throws E, SourceException;
+    T get() throws E;
   }
 
   /**