Remove deprecated exception PdfMergeFailedError

src/ocrmypdf/__init__.py

@@ -21,7 +21,6 @@ from ocrmypdf.exceptions import (
     InputFileError,
     MissingDependencyError,
     OutputFileAccessError,
-    PdfMergeFailedError,
     PriorOcrFoundError,
     SubprocessOutputError,
     TesseractConfigError,

src/ocrmypdf/api.py

@@ -284,8 +284,6 @@ def ocr(  # pylint: disable=unused-argument
             ``"-"``, some final validation steps are not performed (we do not read
             back the stream after it is written).
     Raises:
-        ocrmypdf.PdfMergeFailedError: If the input PDF is malformed, preventing merging
-            with the OCR layer.
         ocrmypdf.MissingDependencyError: If a required dependency program is missing or
             was not found on PATH.
         ocrmypdf.UnsupportedImageFormatError: If the input file type was an image that

src/ocrmypdf/exceptions.py

@@ -47,26 +47,6 @@ class BadArgsError(ExitCodeException):
     exit_code = ExitCode.bad_args
 
 
-class PdfMergeFailedError(ExitCodeException):  # deprecated
-    """An intermediate PDF can't be merged.
-
-    No longer in use.
-    """
-
-    exit_code = ExitCode.input_file
-    message = dedent(
-        '''\
-        Failed to merge PDF image layer with OCR layer
-
-        Usually this happens because the input PDF file is malformed and
-        ocrmypdf cannot correct the problem on its own.
-
-        Try using
-            ocrmypdf --pdf-renderer sandwich  [..other args..]
-        '''
-    )
-
-
 class MissingDependencyError(ExitCodeException):
     """A third-party dependency is missing."""