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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 pkg_config_header_strings(pkg_libraries):
 """ Returns a list of header strings that could be passed to a compiler """

    _, _, header_dirs = pkg_config(pkg_libraries)

    header_strings = []

    for header_dir in header_dirs:
        header_strings.append("-I" + header_dir)

    return header_strings