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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def collect_namespaces(metadata):
 # type: (Mapping[Text, Any]) -> Dict[Text, Text] """Walk through the metadata object, collecting namespace declarations."""

    namespaces = {}  # type: Dict[Text, Text]
    if "$import_metadata" in metadata:
        for value in metadata["$import_metadata"].values():
            add_namespaces(collect_namespaces(value), namespaces)
    if "$namespaces" in metadata:
        add_namespaces(metadata["$namespaces"], namespaces)
    return namespaces