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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 get_env_value(obj, attribute):
 """ Returns the environment variable value for the attribute of the given object. For example `get_env_value(predix.security.uaa, 'uri')` will return value of environment variable PREDIX_SECURITY_UAA_URI. """

    varname = get_env_key(obj, attribute)
    var = os.environ.get(varname)
    if not var:
        raise ValueError("%s must be set in your environment." % varname)

    return var