Copying projection information from one image to another in Python using GDAL

Question

What I want to do is take an image of N bands, merge it with another one of 1 band but preserve the geographic information of the initial image in the merged image.

I can already do the merge but the geo reference information comes out incomplete.

Here is my code:

def array2raster(new_file_name,array,data):
    
    bandas = array.shape[2]
    cols = data.RasterXSize
    rows = data.RasterYSize
    origen = data.GetGeoTransform()
    origenX = origen[0]
    origenY = origen[3]
    pixelWidth=origen[1]
    pixelHeight=origen[5]
    driver = gdal.GetDriverByName("GTiff")
    sr = osr.SpatialReference()
    data.SetProjection(sr.ExportToWkt())
  


    outRaster = driver.Create(new_file_name, cols, rows, bandas, gdal.GDT_Byte)
    outRaster.SetGeoTransform((origenX, pixelWidth, origen[2], origenY,origen[4], pixelHeight))

    for i in range(bandas):
        band = i+1
        banda = array[:,:,i]

        outRaster.GetRasterBand(band).WriteArray(banda)
        outRaster.GetRasterBand(band).SetNoDataValue(np.nan)
        i = i+1

  
    #s_ref =gdal.Copy
    s_ref = osr.SpatialReference()
    s_ref.ImportFromEPSG(4326)
    outRaster.SetProjection(s_ref.ExportToWkt())
    print("se guarda la info con éxito")
    outRaster.FlushCache()