Adding circular string feature using PyQGIS?

Question

I am attempting to add a circular string feature (in this case an arc of a circle). The following code runs without error but doesn't create a feature.

I am using version 3.4.2.

vl = QgsVectorLayer("Polygon", "temp", "memory")
from qgis.PyQt.QtCore import QVariant
pr = vl.dataProvider()
pr.addAttributes([QgsField("name", QVariant.String)])
vl.updateFields() 
cString=QgsCircularString()
cString.setPoints([QgsPoint(306580,167317),QgsPoint(306680,167317),QgsPoint(306680,167817)])
print (cString.hasCurvedSegments())
geom_cString=QgsGeometry(cString)
f = QgsFeature()
f.setGeometry(geom_cString)
f.setAttributes(["One"])
pr.addFeature(f)
vl.updateExtents() 
QgsProject.instance().addMapLayer(vl)

• J. Monticolo: Have you tried : vl = QgsVectorLayer( "LineString" ,"temp" ,"memory") ?
• J. Monticolo: Don't give the solution in your question post, post it directly as answer.

Answer 1

The solution suggested by J. Monticolo in a comment works well:

vl = QgsVectorLayer( "LineString" ,"temp" ,"memory")

• Joseph: Don't forget to accept your answer by clicking the green-faded tick on the left-hand side :)