diff --git a/pyproject.toml b/pyproject.toml
index e08b62f..10ef2a8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,8 @@ authors = [
 ]
 requires-python = ">=3.11"
 dependencies = [
-    "pydantic>=2.11.7",
+    "pydantic_core==2.27.2",
+    "pydantic==2.10.6",
     "sectionproperties>=3.9.0",
 ]
 
diff --git a/src/sectionproperties_tools/__init__.py b/src/sectionproperties_tools/__init__.py
index 58c376e..8cbf538 100644
--- a/src/sectionproperties_tools/__init__.py
+++ b/src/sectionproperties_tools/__init__.py
@@ -2,7 +2,7 @@
 sectionproperties_tools
 """
 
-__version__ = "0.3.1"
+__version__ = "0.3.2"
 
 from .extraction import (extract_properties, envelope_stress_results)
 from .serialize import (
diff --git a/src/sectionproperties_tools/extraction.py b/src/sectionproperties_tools/extraction.py
index 299ad89..6466dde 100644
--- a/src/sectionproperties_tools/extraction.py
+++ b/src/sectionproperties_tools/extraction.py
@@ -6,19 +6,17 @@
 
 def extract_properties(
     analysis_section: Section,
-    subset_to_extract: Optional[str] = None,
+    subset_to_extract: Optional[list[str]] = None,
 ) -> dict[str, float]:
     """
     Extracts the properties from the solved 'analysis_section'.
 
     'analysis_section': a solved Section from sectionproperties.
-    'subset_to_extract': One of {"geometric", "warping", "plastic"}
-        The results extracted will be from one of these sets
-        of properties. If None, then all results will be extracted.
-    'properties_to_extract': If provided, will extract only the 
-        properties from the provided list. If None, will extract
-        all sectionproperties.
-
+    'subset_to_extract': A list of properties to extract from
+        the analysis_section. The names of properties in the
+        solved section will depend on whether or not a non-
+        default material was assigned.
+        If None, then all results will be extracted.
 
         The following properties can be specified when materials
         are _not_ added to the section (i.e. a geometric analysis):