First attempt at ripping out agnostic code into ifcopenshell.api namespace. See #1399.

src/ifcopenshell-python/ifcopenshell/api/geometry/map_representation.py

@@ -0,0 +1,35 @@
+class Usecase:
+    def __init__(self, file, settings=None):
+        self.file = file
+        self.settings = {"representation": None}
+        self.ifc_vertices = []
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        mapping_source = self.get_mapping_source()
+
+        if not mapping_source:
+            return
+
+        zero = self.file.createIfcCartesianPoint((0.0, 0.0, 0.0))
+        x_axis = self.file.createIfcDirection((1.0, 0.0, 0.0))
+        y_axis = self.file.createIfcDirection((0.0, 1.0, 0.0))
+        z_axis = self.file.createIfcDirection((0.0, 0.0, 1.0))
+
+        mapping_target = self.file.createIfcCartesianTransformationOperator3D(x_axis, y_axis, zero, 1, z_axis)
+        mapped_item = self.file.createIfcMappedItem(mapping_source, mapping_target)
+        return self.file.create_entity(
+            "IfcShapeRepresentation",
+            **{
+                "ContextOfItems": self.settings["representation"].ContextOfItems,
+                "RepresentationIdentifier": self.settings["representation"].RepresentationIdentifier,
+                "RepresentationType": "MappedRepresentation",
+                "Items": [mapped_item],
+            }
+        )
+
+    def get_mapping_source(self):
+        for inverse in self.file.get_inverse(self.settings["representation"]):
+            if inverse.is_a("IfcRepresentationMap"):
+                return inverse