code: def addDarkCurrent(self, slope, intercept=None, date=None, info='', error=None):
          '''
          Args:
              slope (np.array)
              intercept (np.array)
              error (numpy.array)
              slope (float): dPx/dExposureTime[sec]
              error (float): absolute
              date (str): "DD Mon YY" e.g. "30 Nov 16"
          '''
          date = _toDate(date)
  
          self._checkShape(slope)
          self._checkShape(intercept)
  
          d = self.coeffs['dark current']
          if intercept is None:
              data = slope
          else:
              data = (slope, intercept)
          d.insert(_insertDateIndex(date, d), [date, info, data, error]f addDarkCurrent(self, slope, intercept=None, date=None, info='', error=None):
          '''
          Args:
              slope (np.array)
              intercept (np.array)
              error (numpy.array)
              slope (float): dPx/dExposureTime[sec]
              error (float): absolute
              date (str): "DD Mon YY" e.g. "30 Nov 16"
          '''
          date = _toDate(date)
  
          self._checkShape(slope)
          self._checkShape(intercept)
  
          d = self.coeffs['dark current']
          if intercept is None:
              data = slope
          else:
              data = (slope, intercept)
          d.insert(_insertDateIndex(date, d), [date, info, data, error])
docs: Args:
              slope (np.array)
              intercept (np.array)
              error (numpy.array)
              slope (float): dPx/dExposureTime[sec]
              error (float): absolute
              date (str): "DD Mon YY" e.g. "30 Nov 16"