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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 add_fortran_to_env(env):
 """Add Builders and construction variables for Fortran to an Environment."""

    try:
        FortranSuffixes = env['FORTRANFILESUFFIXES']
    except KeyError:
        FortranSuffixes = ['.f', '.for', '.ftn']

    #print("Adding %s to fortran suffixes" % FortranSuffixes)
    try:
        FortranPPSuffixes = env['FORTRANPPFILESUFFIXES']
    except KeyError:
        FortranPPSuffixes = ['.fpp', '.FPP']

    DialectAddToEnv(env, "FORTRAN", FortranSuffixes,
                    FortranPPSuffixes, support_module = 1)

    env['FORTRANMODPREFIX'] = ''     # like $LIBPREFIX
    env['FORTRANMODSUFFIX'] = '.mod' # like $LIBSUFFIX

    env['FORTRANMODDIR'] = ''          # where the compiler should place .mod files
    env['FORTRANMODDIRPREFIX'] = ''    # some prefix to $FORTRANMODDIR - similar to $INCPREFIX
    env['FORTRANMODDIRSUFFIX'] = ''    # some suffix to $FORTRANMODDIR - similar to $INCSUFFIX
    env['_FORTRANMODFLAG'] = '$( ${_concat(FORTRANMODDIRPREFIX, FORTRANMODDIR, FORTRANMODDIRSUFFIX, __env__, RDirs, TARGET, SOURCE)} $)'