code: def lmfit_fcn2min(self):
          
          return lambda params, x, data, error: self.function(x, *self.lmfit_parameter_values(params)) - data
docs: The function to minimize when using [lmfit][1].
  
          If overriding this, the replacement function must accept the following
          non-keyword arguments in this order (even if unused):
  
          1. A [`lmfit.Parameters`][2] object.
             The value of each parameter must be passed appropriately to `scipy_data_fitting.Fit.function`
             in the order determined by sorting the parameter keys alphabetically.
             Use `scipy_data_fitting.Fit.lmfit_parameter_values` to get the ordered numerical parameter values.
          2. Independent values: see `scipy_data_fitting.Data.array`.
          3. Dependent values: see `scipy_data_fitting.Data.array`.
          4. The error: see `scipy_data_fitting.Data.error`.
  
  
          The default function computes the difference between the evaluated function and the data.
  
          Default example:
  
              #!python
              lambda params, x, data, error: self.function(x, *self.lmfit_parameter_values(params)) - data
  
          [1]: https://pypi.python.org/pypi/lmfit/
          [2]: http://lmfit.github.io/lmfit-py/parameters.html#the-parameters-class
          [3]: http://docs.scipy.org/doc/numpy/reference/generated/numpy.ndarray.html