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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_geophysical_variables(ds):
    '''
    Returns a list of variable names for the variables detected as geophysical
    variables.

    :param netCDF4.Dataset nc: An open netCDF dataset
    '''

    parameters = []
    for variable in ds.variables:
        if is_geophysical(ds, variable):
            parameters.append(variable)
    return parameters