diff --git a/OddsCollector.Functions.Tests/Tests/OddsApi/Configuration/OddsApiOptions.cs b/OddsCollector.Functions.Tests/Tests/OddsApi/Configuration/OddsApiOptions.cs
index 387ed0d..7154dcf 100644
--- a/OddsCollector.Functions.Tests/Tests/OddsApi/Configuration/OddsApiOptions.cs
+++ b/OddsCollector.Functions.Tests/Tests/OddsApi/Configuration/OddsApiOptions.cs
@@ -4,92 +4,104 @@ namespace OddsCollector.Functions.Tests.Tests.OddsApi.Configuration;
 
 internal class OddsApiOptions
 {
-    private static readonly IEnumerable<(string LeagueString, HashSet<string> ExpectedLeagues)>
-        TestCases = new List<(string LeagueString, HashSet<string> ExpectedLeagues)>
-        {
-            ("league", ["league"]),
-            ("league1;league2", ["league1", "league2"]),
-            ("league1;;league2", ["league1", "league2"]),
-            ("league1;league1", ["league1"])
-        };
-
-    [TestCaseSource(nameof(TestCases))]
-    public void SetLeagues_WithValidLeagueInputString_ReturnsCorrectLeagues(
-        (string LeagueString, HashSet<string> ExpectedLeagues) testCase)
+    [Test]
+    public void SetLeagues_WithOneLeague_ReturnsCorrectLeagues()
+    {
+        var options = new OddsApiClientOptions();
+
+        options.AddLeagues("league");
+
+        options.Leagues.Should().NotBeNull().And.BeEquivalentTo(["league"]);
+    }
+
+    [Test]
+    public void SetLeagues_WithMultipleLeagues_ReturnsCorrectLeagues()
+    {
+        var options = new OddsApiClientOptions();
+
+        options.AddLeagues("league1;league2");
+
+        options.Leagues.Should().NotBeNull().And.BeEquivalentTo(["league1", "league2"]);
+    }
+
+    [Test]
+    public void SetLeagues_WithDuplicateLeagues_ReturnsOneLeague()
+    {
+        var options = new OddsApiClientOptions();
+
+        options.AddLeagues("league1;league1");
+
+        options.Leagues.Should().NotBeNull().And.BeEquivalentTo(["league1"]);
+    }
+
+    [Test]
+    public void SetLeagues_WithEmptyLeague_ReturnsCorrectLeagues()
+    {
+        var options = new OddsApiClientOptions();
+
+        options.AddLeagues("league1;;league2");
+
+        options.Leagues.Should().NotBeNull().And.BeEquivalentTo(["league1", "league2"]);
+    }
+
+    [Test]
+    public void SetLeagues_WithLeadingAndTrailingCharacters_ReturnsCorrectLeagues()
     {
-        // Arrange
         var options = new OddsApiClientOptions();
 
-        // Act
-        options.AddLeagues(testCase.LeagueString);
+        options.AddLeagues("league1\n; league2\r");
 
-        // Assert
-        options.Leagues.Should().NotBeNull().And.BeEquivalentTo(testCase.ExpectedLeagues);
+        options.Leagues.Should().NotBeNull().And.BeEquivalentTo(["league1", "league2"]);
     }
 
     [Test]
     public void SetLeagues_WithNullOrEmptyLeagues_ThrowsException()
     {
-        // Arrange
         var options = new OddsApiClientOptions();
 
-        // Act
         var action = () => options.AddLeagues(string.Empty);
 
-        // Assert
-        action.Should().ThrowExactly<ArgumentException>().WithParameterName("leaguesString");
+        action.Should().ThrowExactly<ArgumentException>().WithParameterName("leagues");
     }
 
     [Test]
     public void SetLeagues_WithNullLeagues_ThrowsException()
     {
-        // Arrange
         var options = new OddsApiClientOptions();
 
-        // Act
         var action = () => options.AddLeagues(null);
 
-        // Assert
-        action.Should().ThrowExactly<ArgumentNullException>().WithParameterName("leaguesString");
+        action.Should().ThrowExactly<ArgumentNullException>().WithParameterName("leagues");
     }
 
     [Test]
     public void SetApiKey_WithValidKey_ReturnsThisKey()
     {
-        // Arrange
         const string key = nameof(key);
         var options = new OddsApiClientOptions();
 
-        // Act
         options.SetApiKey(key);
 
-        // Assert
         options.ApiKey.Should().NotBeNull().And.Be(key);
     }
 
     [Test]
     public void SetApiKey_WithNullApiKey_ThrowsException()
     {
-        // Arrange
         var options = new OddsApiClientOptions();
 
-        // Act
         var action = () => options.SetApiKey(null);
 
-        // Assert
         action.Should().ThrowExactly<ArgumentNullException>().WithParameterName("apiKey");
     }
 
     [Test]
     public void SetApiKey_WithEmptyApiKey_ThrowsException()
     {
-        // Arrange
         var options = new OddsApiClientOptions();
 
-        // Act
         var action = () => options.SetApiKey(string.Empty);
 
-        // Assert
         action.Should().ThrowExactly<ArgumentException>().WithParameterName("apiKey");
     }
 }
diff --git a/OddsCollector.Functions/OddsApi/Configuration/OddsApiClientOptions.cs b/OddsCollector.Functions/OddsApi/Configuration/OddsApiClientOptions.cs
index e9c07f8..b4fb29f 100644
--- a/OddsCollector.Functions/OddsApi/Configuration/OddsApiClientOptions.cs
+++ b/OddsCollector.Functions/OddsApi/Configuration/OddsApiClientOptions.cs
@@ -6,17 +6,14 @@ internal class OddsApiClientOptions
 
     public string ApiKey { get; set; } = string.Empty;
 
-    public void AddLeagues(string? leaguesString)
+    public void AddLeagues(string? leagues)
     {
-        ArgumentException.ThrowIfNullOrEmpty(leaguesString);
+        ArgumentException.ThrowIfNullOrEmpty(leagues);
 
-        foreach (var league in leaguesString.Split(";"))
-        {
-            if (!string.IsNullOrEmpty(league))
-            {
-                Leagues.Add(league);
-            }
-        }
+        var deserialized =
+            leagues.Split(";", StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+
+        Leagues.UnionWith(deserialized);
     }
 
     public void SetApiKey(string? apiKey)