def conductivity(CASRN=None, AvailableMethods=False, Method=None, full_info=True):
def list_methods():<EOL><INDENT>methods = []<EOL>if CASRN in Lange_cond_pure.index:<EOL><INDENT>methods.append(LANGE_COND)<EOL><DEDENT>methods.append(NONE)<EOL>return methods<EOL><DEDENT>if AvailableMethods:<EOL><INDENT>return list_methods()<EOL><DEDENT>if not Method:<EOL><INDENT>Method = list_methods()[<NUM_LIT:0>]<EOL><DEDENT>if Method == LANGE_COND:<EOL><INDENT>kappa = float(Lange_cond_pure.at[CASRN, '<STR_LIT>'])<EOL>if full_info:<EOL><INDENT>T = float(Lange_cond_pure.at[CASRN, '<STR_LIT:T>'])<EOL><DEDENT><DEDENT>elif Method == NONE:<EOL><INDENT>kappa, T = None, None<EOL><DEDENT>else:<EOL><INDENT>raise Exception('<STR_LIT>')<EOL><DEDENT>if full_info:<EOL><INDENT>return kappa, T<EOL><DEDENT>else:<EOL><INDENT>return kappa<EOL><DEDENT>
r'''This function handles the retrieval of a chemical's conductivity.
    Lookup is based on CASRNs. Will automatically select a data source to use
    if no Method is provided; returns None if the data is not available.

    Function has data for approximately 100 chemicals.

    Parameters
    ----------
    CASRN : string
        CASRN [-]

    Returns
    -------
    kappa : float
        Electrical conductivity of the fluid, [S/m]
    T : float, only returned if full_info == True
        Temperature at which conductivity measurement was made
    methods : list, only returned if AvailableMethods == True
        List of methods which can be used to obtain RI with the given inputs

    Other Parameters
    ----------------
    Method : string, optional
        A string for the method name to use, as defined by constants in
        conductivity_methods
    AvailableMethods : bool, optional
        If True, function will determine which methods can be used to obtain
        conductivity for the desired chemical, and will return methods instead
        of conductivity
    full_info : bool, optional
        If True, function will return the temperature at which the conductivity
        reading was made

    Notes
    -----
    Only one source is available in this function. It is:

        * 'LANGE_COND' which is from Lange's Handbook, Table 8.34 Electrical 
        Conductivity of Various Pure Liquids', a compillation of data in [1]_.

    Examples
    --------
    >>> conductivity('7732-18-5')
    (4e-06, 291.15)

    References
    ----------
    .. [1] Speight, James. Lange's Handbook of Chemistry. 16 edition.
       McGraw-Hill Professional, 2005.