code: def addNoise(self, nlf_coeff, date=None, info='', error=None):
          '''
          Args:
              nlf_coeff (list)
              error (float): absolute
              info (str): additional information
              date (str): "DD Mon YY" e.g. "30 Nov 16"
          '''
          date = _toDate(date)
          d = self.coeffs['noise']
          d.insert(_insertDateIndex(date, d), [date, info, nlf_coeff, error]f addNoise(self, nlf_coeff, date=None, info='', error=None):
          '''
          Args:
              nlf_coeff (list)
              error (float): absolute
              info (str): additional information
              date (str): "DD Mon YY" e.g. "30 Nov 16"
          '''
          date = _toDate(date)
          d = self.coeffs['noise']
          d.insert(_insertDateIndex(date, d), [date, info, nlf_coeff, error])
docs: Args:
              nlf_coeff (list)
              error (float): absolute
              info (str): additional information
              date (str): "DD Mon YY" e.g. "30 Nov 16"