reapply requires to is_valid_bibtex

Author: DanielYang59

src/pymatgen/util/provenance.py

@@ -9,6 +9,7 @@
 from io import StringIO
 from typing import TYPE_CHECKING, NamedTuple
 
+from monty.dev import requires
 from monty.json import MontyDecoder, MontyEncoder
 
 from pymatgen.core.structure import Molecule, Structure
@@ -35,6 +36,7 @@
 MAX_BIBTEX_CHARS = 20_000  # maximum number of characters for BibTeX reference
 
 
+@requires(bibtex is not None, "pybtex is not available")
 def is_valid_bibtex(reference: str) -> bool:
     """Use pybtex to validate that a reference is in proper BibTeX format.