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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 write_env_vars(env_vars=None):
 # type: (dict) -> None """Write the dictionary env_vars in the system, as environment variables. Args: env_vars ():
 Returns: """

    env_vars = env_vars or {}
    env_vars['PYTHONPATH'] = ':'.join(sys.path)

    for name, value in env_vars.items():
        os.environ[name] = value