Enhance Array Flattening Utility with Robust Recursive Implementation

src/array_flattener.py

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+from typing import List, Union, Any
+
+def flatten_array(nested_list: List[Any]) -> List[Any]:
+    """
+    Recursively flatten a nested list of arbitrary depth.
+
+    Args:
+        nested_list (List[Any]): A potentially nested list to be flattened.
+
+    Returns:
+        List[Any]: A flattened list with all nested elements extracted.
+
+    Examples:
+        >>> flatten_array([1, [2, 3], [4, [5, 6]]])
+        [1, 2, 3, 4, 5, 6]
+        >>> flatten_array([])
+        []
+        >>> flatten_array([1, 2, 3])
+        [1, 2, 3]
+    """
+    flattened = []
+
+    for item in nested_list:
+        # If the item is a list, recursively flatten it
+        if isinstance(item, list):
+            flattened.extend(flatten_array(item))
+        else:
+            # If not a list, add the item directly
+            flattened.append(item)
+
+    return flattened

tests/test_array_flattener.py

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+import pytest
+from src.array_flattener import flatten_array
+
+def test_flatten_simple_nested_list():
+    """Test flattening a simple nested list."""
+    input_list = [1, [2, 3], 4]
+    assert flatten_array(input_list) == [1, 2, 3, 4]
+
+def test_flatten_deeply_nested_list():
+    """Test flattening a deeply nested list."""
+    input_list = [1, [2, [3, 4]], [5, [6, 7]]]
+    assert flatten_array(input_list) == [1, 2, 3, 4, 5, 6, 7]
+
+def test_flatten_empty_list():
+    """Test flattening an empty list."""
+    assert flatten_array([]) == []
+
+def test_flatten_no_nesting():
+    """Test flattening a list with no nesting."""
+    input_list = [1, 2, 3, 4, 5]
+    assert flatten_array(input_list) == [1, 2, 3, 4, 5]
+
+def test_flatten_mixed_types():
+    """Test flattening a list with mixed types and nesting."""
+    input_list = [1, 'a', [2, 'b'], [3, [4, 'c']]]
+    assert flatten_array(input_list) == [1, 'a', 2, 'b', 3, 4, 'c']
+
+def test_flatten_single_element_lists():
+    """Test flattening lists with single-element nested lists."""
+    input_list = [[1], [2], [3]]
+    assert flatten_array(input_list) == [1, 2, 3]