def _is_number(val):
    """
    Check if argument can be interpreated as number.

    Parameters
    ----------
    val : string, float, int
        Variable to be check if it can be casted to float.

    Returns
    -------
    is_number : bool
        Return if argument can be casted to float.

    """
    try:
        float(val)
        return True
    except ValueError:
        return False
