diff --git a/src/pymatgen/core/composition.py b/src/pymatgen/core/composition.py
index d269c247ff9..03fac2a7412 100644
--- a/src/pymatgen/core/composition.py
+++ b/src/pymatgen/core/composition.py
@@ -25,7 +25,7 @@
 
 if TYPE_CHECKING:
     from collections.abc import Generator, Iterator
-    from typing import Any, ClassVar
+    from typing import Any, ClassVar, Literal
 
     from typing_extensions import Self
 
@@ -774,17 +774,25 @@ def to_reduced_dict(self) -> dict[str, float]:
     def to_weight_dict(self) -> dict[str, float]:
         """
         Returns:
-            dict[str, float] with weight fraction of each component {"Ti": 0.90, "V": 0.06, "Al": 0.04}.
+            dict[str, float]: weight fractions of each component, e.g. {"Ti": 0.90, "V": 0.06, "Al": 0.04}.
         """
         return {str(el): self.get_wt_fraction(el) for el in self.elements}
 
     @property
-    def to_data_dict(self) -> dict[str, Any]:
+    def to_data_dict(
+        self,
+    ) -> dict[
+        Literal["reduced_cell_composition", "unit_cell_composition", "reduced_cell_formula", "elements", "nelements"],
+        Any,
+    ]:
         """
         Returns:
-            A dict with many keys and values relating to Composition/Formula,
-            including reduced_cell_composition, unit_cell_composition,
-            reduced_cell_formula, elements and nelements.
+            dict with the following keys:
+                - reduced_cell_composition
+                - unit_cell_composition
+                - reduced_cell_formula
+                - elements
+                - nelements.
         """
         return {
             "reduced_cell_composition": self.reduced_composition,
diff --git a/src/pymatgen/core/periodic_table.py b/src/pymatgen/core/periodic_table.py
index a981c74578f..63ef361aaf9 100644
--- a/src/pymatgen/core/periodic_table.py
+++ b/src/pymatgen/core/periodic_table.py
@@ -876,7 +876,6 @@ def print_periodic_table(filter_function: Callable | None = None) -> None:
             print(" ".join(row_str))
 
 
-@functools.total_ordering
 class Element(ElementBase):
     """Enum representing an element in the periodic table."""
 
@@ -1597,14 +1596,12 @@ def from_dict(cls, dct: dict) -> Self:
         return cls(dct["element"], dct["oxidation_state"], spin=dct.get("spin"))
 
 
-@functools.total_ordering
 class Specie(Species):
     """This maps the historical grammatically inaccurate Specie to Species
     to maintain backwards compatibility.
     """
 
 
-@functools.total_ordering
 class DummySpecie(DummySpecies):
     """This maps the historical grammatically inaccurate DummySpecie to DummySpecies
     to maintain backwards compatibility.
diff --git a/src/pymatgen/core/structure.py b/src/pymatgen/core/structure.py
index 8e46793c837..9fe9408027e 100644
--- a/src/pymatgen/core/structure.py
+++ b/src/pymatgen/core/structure.py
@@ -19,9 +19,7 @@
 import warnings
 from abc import ABC, abstractmethod
 from collections import defaultdict
-from collections.abc import MutableSequence
 from fnmatch import fnmatch
-from io import StringIO
 from typing import TYPE_CHECKING, Literal, cast, get_args
 
 import numpy as np
@@ -245,7 +243,7 @@ def sites(self) -> list[PeriodicSite] | tuple[PeriodicSite, ...]:
     def sites(self, sites: Sequence[PeriodicSite]) -> None:
         """Set the sites in the Structure."""
         # If self is mutable Structure or Molecule, set _sites as list
-        is_mutable = isinstance(self._sites, MutableSequence)
+        is_mutable = isinstance(self._sites, collections.abc.MutableSequence)
         self._sites: list[PeriodicSite] | tuple[PeriodicSite, ...] = list(sites) if is_mutable else tuple(sites)
 
     @abstractmethod
@@ -1098,9 +1096,8 @@ def __init__(
         self._properties = properties or {}
 
     def __eq__(self, other: object) -> bool:
+        """Define equality by comparing all three attributes: lattice, sites, properties."""
         needed_attrs = ("lattice", "sites", "properties")
-
-        # Return NotImplemented as in https://docs.python.org/3/library/functools.html#functools.total_ordering
         if not all(hasattr(other, attr) for attr in needed_attrs):
             return NotImplemented
 
@@ -1109,8 +1106,10 @@ def __eq__(self, other: object) -> bool:
 
         if other is self:
             return True
+
         if len(self) != len(other):
             return False
+
         if self.lattice != other.lattice:
             return False
         if self.properties != other.properties:
@@ -2982,7 +2981,7 @@ def to(self, filename: PathLike = "", fmt: FileFormats = "", **kwargs) -> str:
             return Prismatic(self).to_str()
         elif fmt in ("yaml", "yml") or fnmatch(filename, "*.yaml*") or fnmatch(filename, "*.yml*"):
             yaml = YAML()
-            str_io = StringIO()
+            str_io = io.StringIO()
             yaml.dump(self.as_dict(), str_io)
             yaml_str = str_io.getvalue()
             if filename:
@@ -3923,7 +3922,7 @@ def to(self, filename: str = "", fmt: str = "") -> str | None:
             return json_str
         elif fmt in {"yaml", "yml"} or fnmatch(filename, "*.yaml*") or fnmatch(filename, "*.yml*"):
             yaml = YAML()
-            str_io = StringIO()
+            str_io = io.StringIO()
             yaml.dump(self.as_dict(), str_io)
             yaml_str = str_io.getvalue()
             if filename: