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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 find_matching_symlink(path, source):
 """Find a symlink under `path` that points at `source`. If source is relative, it is considered relative to `path`. Returns: str: Name of symlink found, or None. """

    def to_abs(target):
        if os.path.isabs(target):
            return target
        else:
            return os.path.normpath(os.path.join(path, target))

    abs_source = to_abs(source)

    for name in os.listdir(path):
        linkpath = os.path.join(path, name)
        if os.path.islink:
            source_ = os.readlink(linkpath)
            if to_abs(source_) == abs_source:
                return name

    return None