diff --git a/math/py-mathics-scanner/Makefile b/math/py-mathics-scanner/Makefile
index 334ffda4b884..4b2a942070bc 100644
--- a/math/py-mathics-scanner/Makefile
+++ b/math/py-mathics-scanner/Makefile
@@ -1,42 +1,43 @@
 # Created by: Thierry Thomas <thierry@pompo.net>
 
 PORTNAME=	Mathics_Scanner
 PORTVERSION=	1.2.4
 CATEGORIES=	math python
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
 
 MAINTAINER=	thierry@FreeBSD.org
 COMMENT=	Tokeniser, char tables, & conversion routines for the Wolfram Language
 
 LICENSE=	GPLv3
 
 BUILD_DEPENDS=	${PYTHON_PKGNAMEPREFIX}ujson>0:devel/py-ujson@${PY_FLAVOR}	\
 		${PYTHON_PKGNAMEPREFIX}click>0:devel/py-click@${PY_FLAVOR}	\
 		${PYTHON_PKGNAMEPREFIX}chardet>0:textproc/py-chardet@${PY_FLAVOR}
 RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}ujson>0:devel/py-ujson@${PY_FLAVOR}	\
 		${PYTHON_PKGNAMEPREFIX}click>0:devel/py-click@${PY_FLAVOR}	\
-		${PYTHON_PKGNAMEPREFIX}chardet>0:textproc/py-chardet@${PY_FLAVOR}
+		${PYTHON_PKGNAMEPREFIX}chardet>0:textproc/py-chardet@${PY_FLAVOR} \
+		${PYTHON_PKGNAMEPREFIX}yaml>0:devel/py-yaml@${PY_FLAVOR}
 TEST_DEPENDS=	gmake:devel/gmake	\
 		${PYTHON_PKGNAMEPREFIX}pytest>0:devel/py-pytest@${PY_FLAVOR}
 
 #USE_GITHUB=	yes
 #GH_ACCOUNT=	Mathics3
 
 USES=		python:3.6+ shebangfix
 USE_PYTHON=	distutils noflavors
 
 NO_ARCH=	yes
 MAKE_ENV+=	PYTHON=${PYTHON_CMD}
 PLIST_SUB+=	VER=${PORTVERSION}
 TEST_TARGET=	check
 TEST_ENV=	${MAKE_ENV}
 
 pre-configure:
 	${CP} ${FILESDIR}/named-characters.yml ${WRKSRC}/mathics_scanner/data/
 
 do-test: install
 	(cd ${TEST_WRKSRC} &&	\
 	${SETENV} ${TEST_ENV} ${GMAKE} ${MAKE_FLAGS} ${MAKEFILE} ${TEST_TARGET})
 
 .include <bsd.port.mk>