code: def execute(cls, ctx, op):
      assert op.merge
      inputs = [ctx[inp.key] for inp in op.inputs]
      ctx[op.outputs[0].key] = next(inp for inp in inputs if inp)
  
imports: from ...serialization.serializables import BoolField
  from ..entity import OutputType, register_fetch_class
  from .base import Operand
  from .core import TileableOperandMixin
  from .fetch import FetchMixin, Fetch
  from .fuse import Fuse, FuseChunkMixin
label_desc: Use image node_id 4 for calling the MergeDictOperand obj's underlying member method code with example usage: obj.execute(cls, ctx, op) without return types