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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_f77_to_env(env):
 """Add Builders and construction variables for f77 to an Environment."""

    try:
        F77Suffixes = env['F77FILESUFFIXES']
    except KeyError:
        F77Suffixes = ['.f77']

    #print("Adding %s to f77 suffixes" % F77Suffixes)
    try:
        F77PPSuffixes = env['F77PPFILESUFFIXES']
    except KeyError:
        F77PPSuffixes = []

    DialectAddToEnv(env, "F77", F77Suffixes, F77PPSuffixes)