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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 construct_stable_id( parent_context, polymorphic_type, relative_char_offset_start, relative_char_offset_end, ):
 """ Contruct a stable ID for a Context given its parent and its character offsets relative to the parent. """

    doc_id, _, parent_doc_char_start, _ = split_stable_id(parent_context.stable_id)
    start = parent_doc_char_start + relative_char_offset_start
    end = parent_doc_char_start + relative_char_offset_end
    return f"{doc_id}::{polymorphic_type}:{start}:{end}"