diff --git a/Cargo.lock b/Cargo.lock
index e3b02f2d..a1547627 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -860,18 +860,18 @@ checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
 
 [[package]]
 name = "memoffset"
-version = "0.6.5"
+version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5aa361d4faea93603064a027415f07bd8e1d5c88c9fbf68bf56a285428fd79ce"
+checksum = "5de893c32cde5f383baa4c04c5d6dbdd735cfd4a794b0debdb2bb1b421da5ff4"
 dependencies = [
  "autocfg",
 ]
 
 [[package]]
 name = "memoffset"
-version = "0.7.1"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5de893c32cde5f383baa4c04c5d6dbdd735cfd4a794b0debdb2bb1b421da5ff4"
+checksum = "d61c719bcfbcf5d62b3a09efa6088de8c54bc0bfcd3ea7ae39fcc186108b8de1"
 dependencies = [
  "autocfg",
 ]
@@ -1248,14 +1248,14 @@ dependencies = [
 
 [[package]]
 name = "pyo3"
-version = "0.17.3"
+version = "0.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "268be0c73583c183f2b14052337465768c07726936a260f480f0857cb95ba543"
+checksum = "ccd4149c8c3975099622b4e1962dac27565cf5663b76452c3e2b66e0b6824277"
 dependencies = [
  "cfg-if",
  "indoc",
  "libc",
- "memoffset 0.6.5",
+ "memoffset 0.8.0",
  "parking_lot",
  "pyo3-build-config",
  "pyo3-ffi",
@@ -1265,9 +1265,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-build-config"
-version = "0.17.3"
+version = "0.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28fcd1e73f06ec85bf3280c48c67e731d8290ad3d730f8be9dc07946923005c8"
+checksum = "9cd09fe469834db21ee60e0051030339e5d361293d8cb5ec02facf7fdcf52dbf"
 dependencies = [
  "once_cell",
  "target-lexicon",
@@ -1275,9 +1275,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-ffi"
-version = "0.17.3"
+version = "0.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0f6cb136e222e49115b3c51c32792886defbfb0adead26a688142b346a0b9ffc"
+checksum = "0c427c9a96b9c5b12156dbc11f76b14f49e9aae8905ca783ea87c249044ef137"
 dependencies = [
  "libc",
  "pyo3-build-config",
@@ -1285,9 +1285,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros"
-version = "0.17.3"
+version = "0.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94144a1266e236b1c932682136dc35a9dee8d3589728f68130c7c3861ef96b28"
+checksum = "16b822bbba9d60630a44d2109bc410489bb2f439b33e3a14ddeb8a40b378a7c4"
 dependencies = [
  "proc-macro2",
  "pyo3-macros-backend",
@@ -1297,9 +1297,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros-backend"
-version = "0.17.3"
+version = "0.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8df9be978a2d2f0cdebabb03206ed73b11314701a5bfe71b0d753b81997777f"
+checksum = "84ae898104f7c99db06231160770f3e40dad6eb9021daddc0fedfa3e41dff10a"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/python/Cargo.toml b/python/Cargo.toml
index 5a4a9c92..a744351b 100644
--- a/python/Cargo.toml
+++ b/python/Cargo.toml
@@ -20,4 +20,4 @@ abi3 = ["pyo3/abi3-py37"]
 
 [dependencies]
 oxigraph = { version = "0.3.10", path="../lib", features = ["http_client"] }
-pyo3 = { version = "0.17", features = ["extension-module"] }
+pyo3 = { version = "0.18", features = ["extension-module"] }
diff --git a/python/src/io.rs b/python/src/io.rs
index 64b1b028..a34377c0 100644
--- a/python/src/io.rs
+++ b/python/src/io.rs
@@ -117,7 +117,6 @@ pub fn parse(
 /// >>> output.getvalue()
 /// b'<http://example.com> <http://example.com/p> "1" .\n'
 #[pyfunction]
-#[pyo3(text_signature = "(input, output, mime_type)")]
 pub fn serialize(input: &PyAny, output: PyObject, mime_type: &str, py: Python<'_>) -> PyResult<()> {
     let output = if let Ok(path) = output.extract::<&str>(py) {
         PyWritable::from_file(path, py)
diff --git a/python/src/model.rs b/python/src/model.rs
index d050516d..864b68d3 100644
--- a/python/src/model.rs
+++ b/python/src/model.rs
@@ -262,11 +262,11 @@ impl From<PyLiteral> for Term {
 #[pymethods]
 impl PyLiteral {
     #[new]
-    #[args(value, "*", datatype = "None", language = "None")]
+    #[pyo3(signature = (value, *, datatype = None, language = None))]
     fn new(
         value: String,
-        language: Option<String>,
         datatype: Option<PyNamedNode>,
+        language: Option<String>,
     ) -> PyResult<Self> {
         Ok(if let Some(language) = language {
             if let Some(datatype) = datatype {
diff --git a/python/src/store.rs b/python/src/store.rs
index 8ae81d43..c7ac180a 100644
--- a/python/src/store.rs
+++ b/python/src/store.rs
@@ -66,7 +66,6 @@ impl PyStore {
     /// >>> store.add(Quad(NamedNode('http://example.com'), NamedNode('http://example.com/p'), Literal('1'), NamedNode('http://example.com/g')))
     /// >>> list(store)
     /// [<Quad subject=<NamedNode value=http://example.com> predicate=<NamedNode value=http://example.com/p> object=<Literal value=1 datatype=<NamedNode value=http://www.w3.org/2001/XMLSchema#string>> graph_name=<NamedNode value=http://example.com/g>>]
-    #[pyo3(text_signature = "($self, quad)")]
     fn add(&self, quad: &PyQuad, py: Python<'_>) -> PyResult<()> {
         py.allow_threads(|| {
             self.inner.insert(quad).map_err(map_storage_error)?;
@@ -87,7 +86,6 @@ impl PyStore {
     /// >>> store.remove(quad)
     /// >>> list(store)
     /// []
-    #[pyo3(text_signature = "($self, quad)")]
     fn remove(&self, quad: &PyQuad, py: Python<'_>) -> PyResult<()> {
         py.allow_threads(|| {
             self.inner.remove(quad).map_err(map_storage_error)?;
@@ -171,16 +169,9 @@ impl PyStore {
     /// >>> store.query('ASK { ?s ?p ?o }')
     /// True
     #[pyo3(
+        signature = (query, *, base_iri = None, use_default_graph_as_union = false, default_graph = None, named_graphs = None),
         text_signature = "($self, query, *, base_iri = None, use_default_graph_as_union = False, default_graph = None, named_graphs = None)"
     )]
-    #[args(
-        query,
-        "*",
-        base_iri = "None",
-        use_default_graph_as_union = "false",
-        default_graph = "None",
-        named_graphs = "None"
-    )]
     fn query(
         &self,
         query: &str,
@@ -236,8 +227,7 @@ impl PyStore {
     /// >>> store.update('DELETE WHERE { <http://example.com> ?p ?o }')
     /// >>> list(store)
     /// []
-    #[pyo3(text_signature = "($self, update, *, base_iri = None)")]
-    #[args(update, "*", base_iri = "None")]
+    #[pyo3(signature = (update, *, base_iri = None), text_signature = "($self, update, *, base_iri = None)")]
     fn update(&self, update: &str, base_iri: Option<&str>, py: Python<'_>) -> PyResult<()> {
         py.allow_threads(|| {
             let update =
@@ -282,8 +272,7 @@ impl PyStore {
     /// >>> store.load(io.BytesIO(b'<foo> <p> "1" .'), "text/turtle", base_iri="http://example.com/", to_graph=NamedNode("http://example.com/g"))
     /// >>> list(store)
     /// [<Quad subject=<NamedNode value=http://example.com/foo> predicate=<NamedNode value=http://example.com/p> object=<Literal value=1 datatype=<NamedNode value=http://www.w3.org/2001/XMLSchema#string>> graph_name=<NamedNode value=http://example.com/g>>]
-    #[pyo3(text_signature = "($self, input, mime_type, *, base_iri = None, to_graph = None)")]
-    #[args(input, mime_type, "*", base_iri = "None", to_graph = "None")]
+    #[pyo3(signature = (input, mime_type, *, base_iri = None, to_graph = None), text_signature = "($self, input, mime_type, *, base_iri = None, to_graph = None)")]
     fn load(
         &self,
         input: PyObject,
@@ -366,8 +355,7 @@ impl PyStore {
     /// >>> store.bulk_load(io.BytesIO(b'<foo> <p> "1" .'), "text/turtle", base_iri="http://example.com/", to_graph=NamedNode("http://example.com/g"))
     /// >>> list(store)
     /// [<Quad subject=<NamedNode value=http://example.com/foo> predicate=<NamedNode value=http://example.com/p> object=<Literal value=1 datatype=<NamedNode value=http://www.w3.org/2001/XMLSchema#string>> graph_name=<NamedNode value=http://example.com/g>>]
-    #[pyo3(text_signature = "($self, input, mime_type, *, base_iri = None, to_graph = None)")]
-    #[args(input, mime_type, "*", base_iri = "None", to_graph = "None")]
+    #[pyo3(signature = (input, mime_type, *, base_iri = None, to_graph = None), text_signature = "($self, input, mime_type, *, base_iri = None, to_graph = None)")]
     fn bulk_load(
         &self,
         input: PyObject,
@@ -446,8 +434,7 @@ impl PyStore {
     /// >>> store.dump(output, "text/turtle", from_graph=NamedNode("http://example.com/g"))
     /// >>> output.getvalue()
     /// b'<http://example.com> <http://example.com/p> "1" .\n'
-    #[pyo3(text_signature = "($self, output, mime_type, *, from_graph = None)")]
-    #[args(output, mime_type, "*", from_graph = "None")]
+    #[pyo3(signature = (output, mime_type, *, from_graph = None), text_signature = "($self, output, mime_type, *, from_graph = None)")]
     fn dump(
         &self,
         output: PyObject,
@@ -502,7 +489,6 @@ impl PyStore {
     /// >>> store.add(Quad(NamedNode('http://example.com'), NamedNode('http://example.com/p'), Literal('1'), NamedNode('http://example.com/g')))
     /// >>> list(store.named_graphs())
     /// [<NamedNode value=http://example.com/g>]
-    #[pyo3(text_signature = "($self)")]
     fn named_graphs(&self) -> GraphNameIter {
         GraphNameIter {
             inner: self.inner.named_graphs(),
@@ -520,7 +506,6 @@ impl PyStore {
     /// >>> store.add_graph(NamedNode('http://example.com/g'))
     /// >>> list(store.named_graphs())
     /// [<NamedNode value=http://example.com/g>]
-    #[pyo3(text_signature = "($self, graph_name)")]
     fn add_graph(&self, graph_name: &PyAny, py: Python<'_>) -> PyResult<()> {
         let graph_name = GraphName::from(&PyGraphNameRef::try_from(graph_name)?);
         py.allow_threads(|| {
@@ -551,7 +536,6 @@ impl PyStore {
     /// []
     /// >>> list(store.named_graphs())
     /// [<NamedNode value=http://example.com/g>]
-    #[pyo3(text_signature = "($self, graph_name)")]
     fn clear_graph(&self, graph_name: &PyAny, py: Python<'_>) -> PyResult<()> {
         let graph_name = GraphName::from(&PyGraphNameRef::try_from(graph_name)?);
         py.allow_threads(|| {
@@ -575,7 +559,6 @@ impl PyStore {
     /// >>> store.remove_graph(NamedNode('http://example.com/g'))
     /// >>> list(store.named_graphs())
     /// []
-    #[pyo3(text_signature = "($self, graph_name)")]
     fn remove_graph(&self, graph_name: &PyAny, py: Python<'_>) -> PyResult<()> {
         let graph_name = GraphName::from(&PyGraphNameRef::try_from(graph_name)?);
         py.allow_threads(|| {
@@ -604,7 +587,6 @@ impl PyStore {
     /// []
     /// >>> list(store.named_graphs())
     /// []
-    #[pyo3(text_signature = "($self)")]
     fn clear(&self, py: Python<'_>) -> PyResult<()> {
         py.allow_threads(|| self.inner.clear().map_err(map_storage_error))
     }
@@ -615,7 +597,6 @@ impl PyStore {
     ///
     /// :rtype: None
     /// :raises IOError: if an I/O error happens during the flush.
-    #[pyo3(text_signature = "($self)")]
     fn flush(&self, py: Python<'_>) -> PyResult<()> {
         py.allow_threads(|| self.inner.flush().map_err(map_storage_error))
     }
@@ -626,7 +607,6 @@ impl PyStore {
     ///
     /// :rtype: None
     /// :raises IOError: if an I/O error happens during the optimization.
-    #[pyo3(text_signature = "($self)")]
     fn optimize(&self, py: Python<'_>) -> PyResult<()> {
         py.allow_threads(|| self.inner.optimize().map_err(map_storage_error))
     }
@@ -652,7 +632,6 @@ impl PyStore {
     /// :type target_directory: str
     /// :rtype: None
     /// :raises IOError: if an I/O error happens during the backup.
-    #[pyo3(text_signature = "($self, target_directory)")]
     fn backup(&self, target_directory: &str, py: Python<'_>) -> PyResult<()> {
         py.allow_threads(|| {
             self.inner