Py4JException when calling Keanu methods in python

[johannespetrat]

Describe the bug
I can import keanu-python, but Py4J throws an error whenever I call a keanu method.
Stacktrace:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/johannespetrat/anaconda2/envs/py37/lib/python3.7/site-packages/keanu/vertex/generated.py", line 162, in ConstantDouble
    return Double(context.jvm_view().ConstantDoubleVertex, constant)
  File "/Users/johannespetrat/anaconda2/envs/py37/lib/python3.7/site-packages/keanu/vertex/base.py", line 21, in __init__
    val = ctor(*(Vertex.__parse_args(args)))
  File "/Users/johannespetrat/anaconda2/envs/py37/lib/python3.7/site-packages/py4j/java_gateway.py", line 1554, in __call__
    answer, self._gateway_client, None, self._fqn)
  File "/Users/johannespetrat/anaconda2/envs/py37/lib/python3.7/site-packages/py4j/protocol.py", line 332, in get_return_value
    format(target_id, ".", name, value))
py4j.protocol.Py4JError: An error occurred while calling None.io.improbable.keanu.vertices.dbl.nonprobabilistic.ConstantDoubleVertex. Trace:
py4j.Py4JException: Constructor io.improbable.keanu.vertices.dbl.nonprobabilistic.ConstantDoubleVertex([class io.improbable.keanu.vertices.dbl.nonprobabilistic.ConstantDoubleVertex]) does not exist
	at py4j.reflection.ReflectionEngine.getConstructor(ReflectionEngine.java:179)
	at py4j.reflection.ReflectionEngine.getConstructor(ReflectionEngine.java:196)
	at py4j.Gateway.invoke(Gateway.java:237)
	at py4j.commands.ConstructorCommand.invokeConstructor(ConstructorCommand.java:80)
	at py4j.commands.ConstructorCommand.execute(ConstructorCommand.java:69)
	at py4j.GatewayConnection.run(GatewayConnection.java:238)
	at java.lang.Thread.run(Thread.java:748)

To Reproduce
Steps to reproduce the behaviour:

1. Create a conda environment with python 3.7.0
2. Run pip install keanu
3. Open the python shell
4. Run import keanu
5. Run keanu.vertext.ConstantDouble(1.)

Expected behavior
This should create a ConstantDoubleVertex.

Desktop (please complete the following information):

• OS: MacOS High Sierra
• Python 3.7.0
• Anaconda 4.4.10

[migwellian]

Hi Johannes, it works when you use Const instead of ConstDouble (the double type is inferred). We'll look into why it fails with ConstDouble and make a fix.

[johannespetrat]

Cool, thanks a lot for clarifying this!