def METHOD_NAME(self, element, X):
    """
    Compute all coefficients of the modular form element in self for
    indices in X.
    TODO: Implement this function.
    EXAMPLES::
        sage: M = ModularForms(6,4).cuspidal_subspace()
        sage: M._compute_coefficients( M.basis()[0], range(1,100) )
        Traceback (most recent call last):
        ...
        NotImplementedError
    """
    raise NotImplementedError