def value_to_fortran(value):
    """Return a Python compatible version of a FORTRAN argument.

    Parameters
    ----------
    value : bool | int | float | str
        A Python friendly representation of the input value.

    Returns
    -------
    fortran_value : str
        A FORTRAN argument.
    """
    if isinstance(value, bool):
        fortran_value = '.{}.'.format(str(value).lower())
    elif isinstance(value, float):
        fortran_value = str(value)
        if 'e' not in fortran_value:
            fortran_value += 'd0'
    return fortran_value
