FileMover

import os,shutil

def checkFileFormat(fileFormat,sourceDir):

        for i in range(len(os.listdir(sourceDir))):
            File = os.listdir(sourceDir)[i]
            (fn,ff) = File.split(".")
            xdir = fileFormat+"/"

            if ( ff == fileFormat ):
                src_dir = sourceDir+str(File)
                dst_dir = xdir+str(File)
                shutil.move(src_dir,dst_dir)

            else:
                print("File format does not exists!")
                break

        print("**DONE**")
        exit()

while( True ):
        file_format = input("File format: ")
        source_dir = str(input("Source directory: "))
        source_dir += "/"

        if ( file_format.isdigit() ):
                print("Numbers is not a format!")
        else:
                break

        if ( not os.path.exists(source_dir) ):
                print("Directory doesn't exists!")
        else:
                break

while( True ):
        try:
                checkFileFormat(file_format,source_dir)
        except Exception:
                pass
        else:
                exit()