docs: add Spark session initialization to PySpark examples and update author info

- Add SparkSession initialization to PySpark and decorator examples in README.md and getting_started.rst
- Update author name from "Data Products GYG" to "Data Products GetYourGuide" in pyproject.toml and conf.py
- Add expectation_count property and list_expectations() method to DataFrameExpectationsSuiteRunner
- Improve test_builder_pattern_immutability test to verify expectation counts and names
- Fix type checker error by making allow_none keyword-only parameter in validate decorator

Author: ryanseq-gyg

README.md

@@ -83,6 +83,10 @@ runner.run(df)
 **PySpark example:**
 ```python
 from dataframe_expectations.expectations_suite import DataFrameExpectationsSuite
+from pyspark.sql import SparkSession
+
+# Initialize Spark session
+spark = SparkSession.builder.appName("example").getOrCreate()
 
 # Build a validation suite (same API as Pandas!)
 suite = (
@@ -113,7 +117,10 @@ runner.run(df)
 **Decorator pattern for automatic validation:**
 ```python
 from dataframe_expectations.expectations_suite import DataFrameExpectationsSuite
-import pandas as pd
+from pyspark.sql import SparkSession
+
+# Initialize Spark session
+spark = SparkSession.builder.appName("example").getOrCreate()
 
 suite = (
     DataFrameExpectationsSuite()

dataframe_expectations/expectations_suite.py

@@ -61,6 +61,20 @@ def __init__(self, expectations: List):
         """
         self.__expectations = tuple(expectations)  # Immutable tuple
 
+    @property
+    def expectation_count(self) -> int:
+        """Return the number of expectations in this runner."""
+        return len(self.__expectations)
+
+    def list_expectations(self) -> List[str]:
+        """
+        Return a list of expectation descriptions in this runner.
+
+        :return: List of expectation descriptions as strings in the format:
+                 "ExpectationName (description)"
+        """
+        return [f"{exp}" for exp in self.__expectations]
+
     def run(
         self,
         data_frame: DataFrameLike,

docs/source/conf.py

@@ -17,8 +17,8 @@
 
 # Project information
 project = 'DataFrame Expectations'
-copyright = '2025, Data Products GYG'
-author = 'Data Products GYG'
+copyright = '2025, GetYourGuide'
+author = 'Data Products GetYourGuide'
 
 # Extensions
 extensions = [

docs/source/getting_started.rst

@@ -62,6 +62,10 @@ PySpark Example
 .. code-block:: python
 
     from dataframe_expectations.expectations_suite import DataFrameExpectationsSuite
+    from pyspark.sql import SparkSession
+
+    # Initialize Spark session
+    spark = SparkSession.builder.appName("example").getOrCreate()
 
     # Build a validation suite (same API as Pandas!)
     suite = (
@@ -93,8 +97,11 @@ Decorator Pattern for Automatic Validation
 
 .. code-block:: python
 
-    import pandas as pd
     from dataframe_expectations.expectations_suite import DataFrameExpectationsSuite
+    from pyspark.sql import SparkSession
+
+    # Initialize Spark session
+    spark = SparkSession.builder.appName("example").getOrCreate()
 
     suite = (
          DataFrameExpectationsSuite()

pyproject.toml

@@ -5,7 +5,7 @@ description = "Python library designed to validate Pandas and PySpark DataFrames
 readme = "README.md"
 requires-python = ">=3.10"
 authors = [
-    {name = "Data Products GYG", email = "[email protected]"}
+    {name = "Data Products GetYourGuide", email = "[email protected]"}
 ]
 
 dependencies = [

tests/test_expectations_suite.py

@@ -207,12 +207,26 @@ def test_builder_pattern_immutability():
     # Build first runner
     runner1 = suite.build()
 
+    # Verify runner1 has exactly 1 expectation
+    assert runner1.expectation_count == 1, "Runner1 should have 1 expectation"
+    expectations_list = runner1.list_expectations()
+    assert len(expectations_list) == 1
+    assert expectations_list[0] == "ExpectationValueGreaterThan ('col1' is greater than 5)"
+
     # Add more expectations to suite
     suite.expect_value_less_than(column_name="col1", value=20)
 
     # Build second runner
     runner2 = suite.build()
 
+    # Verify runner2 has 2 expectations but runner1 is unchanged
+    assert runner1.expectation_count == 1, "Runner1 should still have 1 expectation (immutable)"
+    assert runner2.expectation_count == 2, "Runner2 should have 2 expectations"
+    expectations_list2 = runner2.list_expectations()
+    assert len(expectations_list2) == 2
+    assert expectations_list2[0] == "ExpectationValueGreaterThan ('col1' is greater than 5)"
+    assert expectations_list2[1] == "ExpectationValueLessThan ('col1' is less than 20)"
+
     # Test data
     df = pd.DataFrame({"col1": [10, 15]})