def check_options(options):
    """Check options provided ny user, or assigned by defaults
    are valid arguments.
    
    Keyword arguments:
    options -- contains all options used to fit model (dictionary)
    """
    if options['batch'] not in (True, False):
        raise ValueError(
            'User Error: Invalid argument provided for batch type.')
    if options['sigmoid_type'] not in ('norm', 'logistic', 'gumbel',
        'weibull', 'quick', 'log-quick', 'hyperbolic'):
        raise ValueError(
            'User Error: Sigmoid type specified is not one made available by the module.'
            )
    if options['logspace'] not in (True, False):
        raise ValueError(
            'User/Internal Error: Invalid argument for log-spacing of x-values provided.'
            )
    if options['nafc'] not in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10):
        raise ValueError(
            'Warning: Value provided for nAFC is greater than 10, or less than zero!'
            )
    if isinstance(options['threshold'], (int, float, complex)) is False:
        raise ValueError(
            'Please provide a numerical argument for proportion correct estimate of threshold.'
            )
    if not 0 <= options['threshold'] <= 1:
        raise ValueError(
            'User Error: Value provided for threshold estimate not between zero and one!'
            )
    if isinstance(options['nafc'], int) is False:
        raise ValueError(
            'User Error: Please provide a integer for nAFC argument.')
    if isinstance(options['param_ests'], list) is False:
        raise ValueError(
            'User Error: Please provide a argument of type list for the parameter estimates of the model.'
            )
    if isinstance(options['param_free'], list) is False:
        raise ValueError(
            """User Error: Please provide a argument of type list for the 
                           parameter constraints of the model."""
            )
    if isinstance(options['density'], int) is False:
        raise ValueError(
            'User Error: Please provide a integer for density of grid.')
