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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 load_app(config, **kwargs):
    '''
    Used to load a ``Pecan`` application and its environment based on passed
    configuration.

    :param config: Can be a dictionary containing configuration, a string which
                    represents a (relative) configuration filename

    returns a pecan.Pecan object
    '''
    from .configuration import _runtime_conf, set_config
    set_config(config, overwrite=True)

    for package_name in getattr(_runtime_conf.app, 'modules', []):
        module = __import__(package_name, fromlist=['app'])
        if hasattr(module, 'app') and hasattr(module.app, 'setup_app'):
            app = module.app.setup_app(_runtime_conf, **kwargs)
            app.config = _runtime_conf
            return app
    raise RuntimeError(
        'No app.setup_app found in any of the configured app.modules'
    )