from __future__ import absolute_import, division, print_function, unicode_literals

import numpy as np

class SpyException(Exception):
    '''Base class for spectral module-specific exceptions.'''
    pass

class NaNValueWarning(UserWarning):
    pass

class NaNValueError(ValueError):
    pass

def has_nan(X):
    '''returns True if ndarray `X` contains a NaN value.'''
    return bool(np.isnan(np.min(X)))