def METHOD_NAME(self, **kwargs):
    """
    Print the error message(s). (public)
    Returns:
      str: The output message as a single string.
    """
    # Header
    output = []
    output.append('Running ImageDiffer.py')
    output.append('            File 1: ' + self.__files[0])
    output.append('            File 2: ' + self.__files[1])
    output.append('    Allowed (SSIM): ' + str(self.__allowed))
    output.append('   Computed (SSIM): ' + str(self.__error))
    output.append('     No. of errors: ' + str(len(self.__errors)))
    # Errors
    cnt = 0
    for e in self.__errors:
        cnt += 1
        output.append('')
        output.append('ERROR ' + str(cnt) + ':')
        output.append('  ' + e[0])
        if e[1]:
            output.append('    ' + e[1])
    # Print the output
    if kwargs.pop('output', False):
        print('\n'.join(output))
    # Return the text, as a single string
    return '\n'.join(output)
    # Errors
    cnt = 0
    for e in self.__errors:
        cnt += 1
        output.append('')
        output.append('ERROR ' + str(cnt) + ':')
        output.append('  ' + e[0])
        if e[1]:
            output.append('    ' + e[1])
    # Print the output
    if kwargs.pop('output', False):
        print('\n'.join(output))
    # Return the text, as a single string
    return '\n'.join(output)