Parser does not parse correctly complex node artifacts

[Denis Makogon]

Parser does not parse correctly complex node artifacts definition.

Assume you have node:

    aiorchestra.openstack.compute:
      type: tosca.nodes.openstack.compute
      properties:
        name_or_id: { get_input: compute_name }
      capabilities:
        host:
          properties:
            flavor: { get_input: compute_flavor}
      artifacts:
        image:
          type: tosca.artifacts.openstack.image
          image: { get_input: compute_image }
      requirements:
        - auth: aiorchestra.openstack.authorization

So, when parser returns node template it appears that artifact is not initialized with TOSCA functions correctly, but return a string '{ get_input: compute_image }'