def __init__(self, path, data, command_line):
        """
        It copies the content of self.path from the initialization routine of
        the :class:`Data <data.Data>` class, and defines a handful of useful
        methods, that every likelihood might need.

        If the nuisance parameters required to compute this likelihood are not
        defined (either fixed or varying), the code will stop.

        Parameters
        ----------
        data : class
            Initialized instance of :class:`Data <data.Data>`
        command_line : NameSpace
            NameSpace containing the command line arguments

        """

        self.name = self.__class__.__name__
        self.folder = os.path.abspath(os.path.join(
            data.path['MontePython'], 'likelihoods', self.name))
        if not data.log_flag:
            path = os.path.join(command_line.folder, 'log.param')

        # Define some default fields
        self.data_directory = ''

        # Store all the default fields stored, for the method read_file.
        self.default_values = ['data_directory']

        # Recover the values potentially read in the input.param file.
        if hasattr(data, self.name):
            exec("attributes = [e for e in dir(data.%s) if e.find('__') == -1]" % self.name)
            for elem in attributes:
                exec("setattr(self, elem, getattr(data.%s, elem))" % self.name)

        # Read values from the data file
        self.read_from_file(path, data, command_line)

        # Default state
        self.need_update = True

        # Check if the nuisance parameters are defined
        error_flag = False
        try:
            for nuisance in self.use_nuisance:
                if nuisance not in data.get_mcmc_parameters(['nuisance']):
                    error_flag = True
                    warnings.warn(
                        nuisance + " must be defined, either fixed or " +
                        "varying, for %s likelihood" % self.name)
            self.nuisance = self.use_nuisance
        except __HOLE__:
            self.use_nuisance = []
            self.nuisance = []

        # If at least one is missing, raise an exception.
        if error_flag:
            raise io_mp.LikelihoodError(
                "Check your nuisance parameter list for your set of"
                "experiments")

        # Append to the log.param the value used (WARNING: so far no comparison
        # is done to ensure that the experiments share the same parameters)
        if data.log_flag:
            io_mp.log_likelihood_parameters(self, command_line)
dataset/ETHPy150Open baudren/montepython_public/montepython/likelihood_class.py/Likelihood.__init__