def METHOD_NAME(counts, suppress_cast=False):
    """Validate and convert input to an acceptable counts vector type.
    Note: may not always return a copy of `counts`!
    """
    counts = np.asarray(counts)
    try:
        if not np.all(np.isreal(counts)):
            raise Exception
    except Exception:
        raise ValueError("Counts vector must contain real-valued entries.")
    if counts.ndim != 1:
        raise ValueError("Only 1-D vectors are supported.")
    elif (counts < 0).any():
        raise ValueError("Counts vector cannot contain negative values.")
    return counts