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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 remove_BC(self, pores=None):
 r""" Removes all boundary conditions from the specified pores Parameters pores : array_like The pores from which boundary conditions are to be removed. If no pores are specified, then BCs are removed from all pores. No error is thrown if the provided pores do not have any BCs assigned. """

        if pores is None:
            pores = self.Ps
        if 'pore.bc_value' in self.keys():
            self['pore.bc_value'][pores] = np.nan
        if 'pore.bc_rate' in self.keys():
            self['pore.bc_rate'][pores] = np.nan