diff --git a/pyshacl/constraints/advanced/__init__.py b/pyshacl/constraints/advanced/__init__.py
index 841bdc9..61e1539 100644
--- a/pyshacl/constraints/advanced/__init__.py
+++ b/pyshacl/constraints/advanced/__init__.py
@@ -7,7 +7,7 @@
 import typing
 from typing import Dict, List
 
-from rdflib import Literal
+from rdflib import Literal, URIRef
 
 from pyshacl.constraints.constraint_component import ConstraintComponent
 from pyshacl.consts import SH, SH_message
@@ -35,7 +35,7 @@ def __init__(self, shape: 'Shape'):
             )
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return [SH_expression]
 
     @classmethod
diff --git a/pyshacl/constraints/constraint_component.py b/pyshacl/constraints/constraint_component.py
index a70452e..cf02af9 100644
--- a/pyshacl/constraints/constraint_component.py
+++ b/pyshacl/constraints/constraint_component.py
@@ -68,7 +68,7 @@ def __init__(self, shape: 'Shape'):
 
     @classmethod
     @abc.abstractmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         raise NotImplementedError()  # pragma: no cover
 
     @classmethod
diff --git a/pyshacl/constraints/core/cardinality_constraints.py b/pyshacl/constraints/core/cardinality_constraints.py
index 18b63d2..15ed91a 100644
--- a/pyshacl/constraints/core/cardinality_constraints.py
+++ b/pyshacl/constraints/core/cardinality_constraints.py
@@ -5,7 +5,7 @@
 from typing import Dict, List, Optional
 
 from rdflib.namespace import XSD
-from rdflib.term import Literal
+from rdflib.term import Literal, URIRef
 
 from pyshacl.constraints.constraint_component import ConstraintComponent
 from pyshacl.consts import SH
@@ -66,7 +66,7 @@ def __init__(self, shape, min_count_objects: Optional[List[RDFNode]] = None):
             )
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return [SH_minCount]
 
     @classmethod
@@ -153,7 +153,7 @@ def __init__(self, shape, max_count_objects: Optional[List[RDFNode]] = None):
             )
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return [SH_maxCount]
 
     @classmethod
diff --git a/pyshacl/constraints/core/logical_constraints.py b/pyshacl/constraints/core/logical_constraints.py
index 7a27508..8f9a45b 100644
--- a/pyshacl/constraints/core/logical_constraints.py
+++ b/pyshacl/constraints/core/logical_constraints.py
@@ -48,7 +48,7 @@ def __init__(self, shape):
         self.not_list = not_list
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_not]
 
     @classmethod
@@ -151,7 +151,7 @@ def __init__(self, shape):
         self.and_list = and_list
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_and]
 
     @classmethod
@@ -247,7 +247,7 @@ def __init__(self, shape):
         self.or_list = or_list
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_or]
 
     @classmethod
@@ -343,7 +343,7 @@ def __init__(self, shape):
         self.xone_nodes = xone_nodes
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_xone]
 
     @classmethod
diff --git a/pyshacl/constraints/core/other_constraints.py b/pyshacl/constraints/core/other_constraints.py
index 342cc3d..d57818d 100644
--- a/pyshacl/constraints/core/other_constraints.py
+++ b/pyshacl/constraints/core/other_constraints.py
@@ -54,7 +54,7 @@ def __init__(self, shape):
         self.in_vals = in_vals
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_in]
 
     @classmethod
@@ -133,7 +133,7 @@ def __init__(self, shape):
         self.property_shapes = list(self.shape.objects(SH_property))
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_closed, SH_ignoredProperties]
 
     @classmethod
@@ -280,7 +280,7 @@ def __init__(self, shape):
         self.has_value_set = has_value_set
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_hasValue]
 
     @classmethod
diff --git a/pyshacl/constraints/core/property_pair_constraints.py b/pyshacl/constraints/core/property_pair_constraints.py
index 29c3e5a..a393432 100644
--- a/pyshacl/constraints/core/property_pair_constraints.py
+++ b/pyshacl/constraints/core/property_pair_constraints.py
@@ -46,7 +46,7 @@ def __init__(self, shape):
         self.property_compare_set = property_compare_set
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_equals]
 
     @classmethod
@@ -173,7 +173,7 @@ def __init__(self, shape):
         self.property_compare_set = property_compare_set
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_disjoint]
 
     @classmethod
@@ -298,7 +298,7 @@ def __init__(self, shape):
         self.property_compare_set = property_compare_set
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_lessThan]
 
     @classmethod
@@ -449,7 +449,7 @@ def __init__(self, shape):
         self.property_compare_set = property_compare_set
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_lessThanOrEquals]
 
     @classmethod
diff --git a/pyshacl/constraints/core/shape_based_constraints.py b/pyshacl/constraints/core/shape_based_constraints.py
index 634e3bb..0388c0e 100644
--- a/pyshacl/constraints/core/shape_based_constraints.py
+++ b/pyshacl/constraints/core/shape_based_constraints.py
@@ -61,7 +61,7 @@ def __init__(self, shape):
         self.property_shapes = property_shapes
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_property]
 
     @classmethod
@@ -155,7 +155,7 @@ def __init__(self, shape):
         self.node_shapes = node_shapes
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_node]
 
     @classmethod
@@ -316,7 +316,7 @@ def __init__(self, shape):
         self.is_disjoint = is_disjoint
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_qualifiedValueShape, SH_qualifiedMinCount, SH_qualifiedValueShapesDisjoint, SH_qualifiedMaxCount]
 
     @classmethod
diff --git a/pyshacl/constraints/core/string_based_constraints.py b/pyshacl/constraints/core/string_based_constraints.py
index 5adf9a1..fedc612 100644
--- a/pyshacl/constraints/core/string_based_constraints.py
+++ b/pyshacl/constraints/core/string_based_constraints.py
@@ -43,7 +43,7 @@ def __init__(self, shape):
         self.allow_multi_rules = True
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         raise NotImplementedError()
 
     @classmethod
@@ -132,7 +132,7 @@ def __init__(self, shape):
         self.string_rules = patterns_found
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_minLength]
 
     @classmethod
@@ -212,7 +212,7 @@ def __init__(self, shape):
         self.string_rules = patterns_found
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_maxLength]
 
     @classmethod
@@ -280,7 +280,7 @@ def __init__(self, shape):
             self.flags = None
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_pattern]
 
     @classmethod
@@ -358,7 +358,7 @@ def __init__(self, shape):
         self.string_rules = language_ins_found
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_languageIn]
 
     @classmethod
@@ -452,7 +452,7 @@ def __init__(self, shape):
         self.string_rules = {is_unique_lang.value}
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_uniqueLang]
 
     @classmethod
diff --git a/pyshacl/constraints/core/value_constraints.py b/pyshacl/constraints/core/value_constraints.py
index ce83eb7..fb2c066 100644
--- a/pyshacl/constraints/core/value_constraints.py
+++ b/pyshacl/constraints/core/value_constraints.py
@@ -8,7 +8,7 @@
 
 import rdflib
 from rdflib.namespace import XSD
-from rdflib.term import Literal
+from rdflib.term import Literal, URIRef
 
 from pyshacl.constraints.constraint_component import ConstraintComponent
 from pyshacl.consts import (
@@ -70,7 +70,7 @@ def __init__(self, shape):
         self.class_rules = class_rules
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return [SH_class]
 
     @classmethod
@@ -184,7 +184,7 @@ def __init__(self, shape):
         self.datatype_rule = datatype_rules[0]
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return [SH_datatype]
 
     @classmethod
@@ -292,7 +292,7 @@ def __init__(self, shape):
         self.nodekind_rule = nodekind_rules[0]
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return [SH_nodeKind]
 
     @classmethod
diff --git a/pyshacl/constraints/core/value_range_constraints.py b/pyshacl/constraints/core/value_range_constraints.py
index a4b285e..2ae2bac 100644
--- a/pyshacl/constraints/core/value_range_constraints.py
+++ b/pyshacl/constraints/core/value_range_constraints.py
@@ -45,7 +45,7 @@ def __init__(self, shape):
         self.min_vals = min_vals
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_minExclusive]
 
     @classmethod
@@ -135,7 +135,7 @@ def __init__(self, shape):
         self.min_vals = min_vals
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_minInclusive]
 
     @classmethod
@@ -225,7 +225,7 @@ def __init__(self, shape):
         self.max_vals = max_vals
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_maxExclusive]
 
     @classmethod
@@ -315,7 +315,7 @@ def __init__(self, shape):
         self.max_vals = max_vals
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         return [SH_maxInclusive]
 
     @classmethod
diff --git a/pyshacl/constraints/sparql/sparql_based_constraint_components.py b/pyshacl/constraints/sparql/sparql_based_constraint_components.py
index 92c1ff9..0dcf14e 100644
--- a/pyshacl/constraints/sparql/sparql_based_constraint_components.py
+++ b/pyshacl/constraints/sparql/sparql_based_constraint_components.py
@@ -47,7 +47,7 @@ def __init__(self, constraint, shape: 'Shape', validator):
         self.query_helper.collect_prefixes()
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[rdflib.URIRef]:
         # TODO:coverage: this is never used for this constraint?
         return []
 
diff --git a/pyshacl/constraints/sparql/sparql_based_constraints.py b/pyshacl/constraints/sparql/sparql_based_constraints.py
index 4fc8bf4..6605111 100644
--- a/pyshacl/constraints/sparql/sparql_based_constraints.py
+++ b/pyshacl/constraints/sparql/sparql_based_constraints.py
@@ -5,6 +5,7 @@
 from typing import Dict, List
 
 import rdflib
+from rdflib import URIRef
 
 from pyshacl.constraints.constraint_component import ConstraintComponent
 from pyshacl.consts import SH, SH_deactivated, SH_message, SH_select
@@ -81,7 +82,7 @@ def __init__(self, shape):
         self.sparql_constraints = sparql_constraints
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return [SH_sparql]
 
     @classmethod
diff --git a/pyshacl/extras/js/constraint.py b/pyshacl/extras/js/constraint.py
index 1b7b228..a2f076b 100644
--- a/pyshacl/extras/js/constraint.py
+++ b/pyshacl/extras/js/constraint.py
@@ -3,7 +3,7 @@
 import typing
 from typing import Dict, List
 
-from rdflib import Literal
+from rdflib import Literal, URIRef
 
 from pyshacl.constraints import ConstraintComponent
 from pyshacl.consts import SH, SH_js, SH_message
@@ -70,7 +70,7 @@ def __init__(self, shape: 'Shape'):
         self.js_impls = [JSConstraintImpl(shape.sg, j) for j in js_decls]
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return [SH_js]
 
     @classmethod
diff --git a/pyshacl/extras/js/constraint_component.py b/pyshacl/extras/js/constraint_component.py
index defe46c..19572a9 100644
--- a/pyshacl/extras/js/constraint_component.py
+++ b/pyshacl/extras/js/constraint_component.py
@@ -3,7 +3,7 @@
 import typing
 from typing import Any, Dict, List, Tuple, Union
 
-from rdflib import Literal
+from rdflib import Literal, URIRef
 
 from pyshacl.constraints import ConstraintComponent
 from pyshacl.constraints.constraint_component import CustomConstraintComponent
@@ -65,7 +65,7 @@ def bind_params(self):
         self.param_bind_map = bind_map
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         # TODO:coverage: this is never used for this constraint?
         return []
 
diff --git a/pyshacl/extras/js/target.py b/pyshacl/extras/js/target.py
index eaf04d9..87a8191 100644
--- a/pyshacl/extras/js/target.py
+++ b/pyshacl/extras/js/target.py
@@ -35,7 +35,7 @@ def __init__(self, target_type: 'JSTargetType', target_declaration, shape: 'Shap
         self.params_kv = params_kv  # type: dict
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return []
 
     @classmethod
diff --git a/pyshacl/target.py b/pyshacl/target.py
index 2df6c36..bd4cf8f 100644
--- a/pyshacl/target.py
+++ b/pyshacl/target.py
@@ -2,6 +2,8 @@
 from typing import List, Sequence, Type, Union
 from warnings import warn
 
+from rdflib import URIRef
+
 from .constraints import ConstraintComponent
 from .consts import SH, RDF_type, RDFS_subClassOf, SH_parameter, SH_select, SH_SPARQLTargetType
 from .errors import ConstraintLoadError, ShapeLoadError
@@ -105,7 +107,7 @@ def __init__(self, target_type, target_declaration, shape, param_vals=None):
         self.param_vals = param_vals
 
     @classmethod
-    def constraint_parameters(cls):
+    def constraint_parameters(cls) -> List[URIRef]:
         return []
 
     @classmethod