Custom VDU Capability not handled.

While adding the custom VDU capability for nfv definitions for:
1) tosca.datatypes.compute.Container.Architecture.CPUAllocation
2) tosca.datatypes.compute.Container.Architecture.NUMA

tosca -parser throws error.

Added the custom definition as follows:

node_types:
  tosca.nodes.nfv.VDU.ADVA:
    derived_from: tosca.nodes.nfv.VDU
    capabilities:
      nfv_compute:
        type: tosca.capabilities.Compute.Container.Architecture

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Needs enhancement in the capabilities.py and properties.py to take the custom definitions.