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

src/ifcopenshell-python/ifcopenshell/api/structural/edit_structural_boundary_condition.py

@@ -0,0 +1,19 @@
+class Usecase:
+    def __init__(self, file, settings={}):
+        self.file = file
+        self.settings = {
+            "condition": None,
+            "attributes": {}
+        }
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        for name, data in self.settings["attributes"].items():
+            if data["type"] == "string" or data["type"] == "null":
+                value = data["value"]
+            elif data["type"] == "IfcBoolean":
+                value = self.file.createIfcBoolean(data["value"])
+            else:
+                value = self.file.create_entity(data["type"], data["value"])
+            setattr(self.settings["condition"], name, value)