add property Elements to Entry class

pymatgen/entries/__init__.py

@@ -9,13 +9,17 @@
 from __future__ import annotations
 
 from abc import ABCMeta, abstractmethod
-from typing import Literal
+from typing import TYPE_CHECKING, Literal
 
 import numpy as np
 from monty.json import MSONable
 
 from pymatgen.core.composition import Composition
 
+if TYPE_CHECKING:
+    from pymatgen.core import DummySpecies, Element, Species
+
+
 __author__ = "Shyue Ping Ong, Anubhav Jain, Ayush Gupta"
 __copyright__ = "Copyright 2020, The Materials Project"
 __version__ = "1.1"
@@ -34,46 +38,45 @@ class Entry(MSONable, metaclass=ABCMeta):
 
     """
 
-    def __init__(
-        self,
-        composition: Composition | str | dict[str, float],
-        energy: float,
-    ) -> None:
+    def __init__(self, composition: Composition | str | dict[str, float], energy: float) -> None:
         """
         Initializes an Entry.
 
         Args:
             composition (Composition): Composition of the entry. For
-                flexibility, this can take the form of all the typical input
-                taken by a Composition, including a {symbol: amt} dict,
-                a string formula, and others.
+                flexibility, this can take the form of all the typical input taken by a
+                Composition, including a {symbol: amt} dict, a string formula, and others.
             energy (float): Energy of the entry.
         """
         self._composition = Composition(composition)
         self._energy = energy
 
     @property
     def is_element(self) -> bool:
-        """:return: Whether composition of entry is an element."""
-        # NOTE _composition rather than composition as GrandPDEntry
-        # edge case exists if we have a compound where chempots are
-        # given for all bar one element type
+        """Whether composition of entry is an element."""
+        # NOTE _composition rather than composition as GrandPDEntry edge case exists if we
+        # have a compound where chempots are given for all bar one element type
         return self._composition.is_element
 
     @property
     def composition(self) -> Composition:
-        """:return: the composition of the entry."""
+        """The composition of the entry."""
         return self._composition
 
     @property
     @abstractmethod
     def energy(self) -> float:
-        """:return: the energy of the entry."""
+        """The energy of the entry."""
         raise NotImplementedError
 
+    @property
+    def elements(self) -> list[Element | Species | DummySpecies]:
+        """The set of elements in the entry."""
+        return self._composition.elements
+
     @property
     def energy_per_atom(self) -> float:
-        """:return: the energy per atom of the entry."""
+        """The energy per atom of the entry."""
         return self.energy / self.composition.num_atoms
 
     def __repr__(self):