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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 split_mapping(pair_str):
 """Split the ``str`` in ``pair_str`` at ``'='`` Warn if key needs to be stripped """

    orig_key, value = pair_str.split("=", 1)
    key = orig_key.strip()
    if key != orig_key:
        warnings.warn(
            "Mapping key {} has leading or trailing space".format(repr(orig_key)),
            LeadingTrailingSpaceInKey,
        )
    return key, value