You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: easting_northing.rb
    path of file: ./repos/geocoder/lib
    
    the code of the file until where you have to start completion: module Geocoder
  class EastingNorthing
    attr_reader :easting, :northing, :lat_lng

    def initialize(opts)
      @easting = opts[:easting]
      @northing = opts[:northing]

      @lat_lng = to_WGS84(to_osgb_36)
    end

    private

    def to_osgb_36
     
    
    def to_osgb_36
      osgb_fo  = 0.9996012717
      northing0 = -100_000.0
      easting0 = 400_000.0
      phi0 = deg_to_rad(49.0)
      lambda0 = deg_to_rad(-2.0)
      a = 6_377_563.396
      b = 6_356_256.909
      eSquared = ((a * a) - (b * b)) / (a * a)
      phi = 0.0
      lambda = 0.0
      n = (a - b) / (a + b)
      m = 0.0
      phiPrime = ((northing - northing0) / (a * osgb_fo)) + phi0

      while (northing - northing0 - m) >= 0.001
        m =
          (b * osgb_fo)\
            * (((1 + n + ((5.0 / 4.0) * n * n) + ((5.0 / 4.0) * n * n * n))\
              * (phiPrime - phi0))\
              - (((3 * n) + (3 * n * n) + ((21.0 / 8.0) * n * n * n))\
                * Math.sin(phiPrime - phi0)\
                * Math.cos(phiPrime + phi0))\
              + ((((15.0 / 8.0) * n * n) + ((15.0 / 8.0) * n * n * n))\
                * Math.sin(2.0 * (phiPrime - phi0))\
                * Math.cos(2.0 * (phiPrime + phi0)))\
              - (((35.0 / 24.0) * n * n * n)\
                * Math.sin(3.0 * (phiPrime - phi0))\
                * Math.cos(3.0 * (phiPrime + phi0))))

        phiPrime += (northing - northing0 - m) / (a * osgb_fo)
      end