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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def lg_solubility_ratio(electrolytes, gas, units=None, warn=True):
 """ Returns the log10 value of the solubilty ratio Implements equation 16, p 156. from Schumpe (1993) Parameters electrolytes : dict Mapping substance key (one in ``p_ion_rM``) to concentration. gas : str Substance key for the gas (one in ``p_gas_rM``). units : object (optional) object with attribute: molar warn : bool (default: True) Emit UserWarning when 'F-' among electrolytes. """

    if units is None:
        M = 1
    else:
        M = units.molar
    if warn and 'F-' in electrolytes:
        warnings.warn("In Schumpe 1993: data for fluoride uncertain.")
    return sum([(p_gas_rM[gas]/M+p_ion_rM[k]/M)*v for k, v in electrolytes.items()])