How to use the canmatrix.copy.copy_frame function in canmatrix

#
# create target Matrix
#

db3 = canmatrix.CanMatrix()

#
# Here a new Can-Matrix can be  'programmed':
# -----------------------------------------------------
#

# Copy Can-ID 1234 from second CAN-Matrix to target-Matrix
canmatrix.copy.copy_frame(1234, db2, db3)

# Copy frame "Engine_123" from first CAN-Matrix to target-Matrix
canmatrix.copy.copy_frame("Engine_123", db1, db3)

# Copy ECU (with all Frames) "Gateway" from first CAN-Matrix to target-Matrix
canmatrix.copy.copy_ecu_with_frames("Gateway", db1, db3)

#
# -----------------------------------------------------
#


#
#
# export the new (target)-Matrix for example as .dbc:
#

canmatrix.formats.dumpp(db3, "target.dbc")

def merge(self, mergeArray):  # type: (typing.Sequence[CanMatrix]) -> None
        """Merge multiple Matrices to this Matrix.

        Try to copy all Frames and all environment variables from source Matrices. Don't make duplicates.
        Log collisions.

        :param list of Matrix mergeArray: list of source CAN Matrices to be merged to to self.
        """
        for dbTemp in mergeArray:  # type: CanMatrix
            for frame in dbTemp.frames:
                copyResult = canmatrix.copy.copy_frame(frame.arbitration_id, dbTemp, self)
                if copyResult is False:
                    logger.error(
                        "ID Conflict, could not copy/merge frame " + frame.name + "  %xh " % frame.arbitration_id.id + self.frame_by_id(frame.arbitration_id).name
                    )
            for envVar in dbTemp.env_vars:
                if envVar not in self.env_vars:
                    self.add_env_var(envVar, dbTemp.env_vars[envVar])
                else:
                    logger.error(
                        "Name Conflict, could not copy/merge EnvVar " + envVar)

# import of a second CAN-Matrix (*.dbc, *.dbf, *.kcd, *.arxml)
db2 = canmatrix.formats.loadp("second.dbc", flat_import=True)

#
# create target Matrix
#

db3 = canmatrix.CanMatrix()

#
# Here a new Can-Matrix can be  'programmed':
# -----------------------------------------------------
#

# Copy Can-ID 1234 from second CAN-Matrix to target-Matrix
canmatrix.copy.copy_frame(1234, db2, db3)

# Copy frame "Engine_123" from first CAN-Matrix to target-Matrix
canmatrix.copy.copy_frame("Engine_123", db1, db3)

# Copy ECU (with all Frames) "Gateway" from first CAN-Matrix to target-Matrix
canmatrix.copy.copy_ecu_with_frames("Gateway", db1, db3)

#
# -----------------------------------------------------
#


#
#
# export the new (target)-Matrix for example as .dbc:
#