How to use the pyqtgraph.Qt.QtGui.QPushButton function in pyqtgraph

self.corrShape = None
        self.cropShape = None
        self.xlim = None
        self.ylim = None
        self.shape = self.main.shape

        # Title
        recTitle = QtGui.QLabel('<h2><strong>Recording</strong></h2>')
        recTitle.setTextFormat(QtCore.Qt.RichText)
        self.setFrameStyle(QtGui.QFrame.Panel | QtGui.QFrame.Raised)

        # Folder and filename fields
        self.folderEdit = QtGui.QLineEdit(self.initialDir)
        openFolderButton = QtGui.QPushButton('Open')
        openFolderButton.clicked.connect(self.openFolder)
        loadFolderButton = QtGui.QPushButton('Browse')
        loadFolderButton.clicked.connect(self.loadFolder)
        self.filenameEdit = QtGui.QLineEdit('filename')
        self.name = os.path.join(self.folderEdit.text(),
                                 self.filenameEdit.text())

        # Snap button
        self.snapButton = QtGui.QPushButton('Snap')
        self.snapButton.setStyleSheet("font-size:16px")
        self.snapButton.setSizePolicy(QtGui.QSizePolicy.Preferred,
                                      QtGui.QSizePolicy.Expanding)
        self.snapButton.setToolTip('Ctrl+S')
        self.snapButton.clicked.connect(self.snap)

        # REC button
        self.recButton = QtGui.QPushButton('REC')
        self.recButton.setStyleSheet("font-size:16px")

def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.setFrameStyle(QtGui.QFrame.Panel | QtGui.QFrame.Raised)

        # Widgets
        self.graph = MoleculesGraph(self)
        self.enableBox = QtGui.QCheckBox('Enable')
        self.enableBox.setEnabled(False)
        self.enableBox.stateChanged.connect(self.graph.getTime)
        self.lockButton = QtGui.QPushButton('Lock (no anda)')
        self.lockButton.setCheckable(True)
        self.lockButton.clicked.connect(self.toggleLock)
        self.lockButton.setSizePolicy(QtGui.QSizePolicy.Preferred,
                                      QtGui.QSizePolicy.Expanding)
        self.alphaLabel = QtGui.QLabel('Alpha')
        self.alphaLabel.setAlignment((QtCore.Qt.AlignRight |
                                      QtCore.Qt.AlignVCenter))
        self.alphaEdit = QtGui.QLineEdit('5')
        self.alphaEdit.setFixedWidth(40)

        # GUI layout
        grid = QtGui.QGridLayout()
        self.setLayout(grid)
        grid.addWidget(self.graph, 0, 0, 1, 5)
        grid.addWidget(self.enableBox, 1, 0)
        grid.addWidget(self.alphaLabel, 1, 1)

self.editor = None

        self.table = QtGui.QTableWidget()
        self.table.setColumnCount(2)
        self.table.horizontalHeader().hide()
        self.table.verticalHeader().hide()
        self.table.horizontalHeader().setStretchLastSection(True)
        self.table.setSelectionBehavior(QtGui.QAbstractItemView.SelectRows)
        # self.table.horizontalHeader().setResizeMode(QtGui.QHeaderView.Interactive)

        self.setRows(0)

        buttonAdd = QtGui.QPushButton('Add')
        buttonRemove = QtGui.QPushButton('Remove')
        buttonEdit = QtGui.QPushButton('Edit')
        buttonCopy = QtGui.QPushButton('Copy')
        buttonActive = QtGui.QPushButton('Set Active')

        buttonCopy.clicked.connect(self.copyFile)
        buttonEdit.clicked.connect(self.editFile)
        buttonActive.clicked.connect(self.setDefault)
        buttonAdd.clicked.connect(self.addFile)
        buttonRemove.clicked.connect(self.removeFile)

        buttonL = QtGui.QGridLayout()
        buttonL.addWidget(buttonAdd, 0, 0)
        buttonL.addWidget(buttonRemove, 0, 1)
        buttonL.addWidget(buttonEdit, 0, 2)
        buttonL.addWidget(buttonCopy, 1, 0)
        buttonL.addWidget(buttonActive, 1, 1, 1, 2)
        # buttonL.addStretch()

def setText(self, text=None, temporary=False):
        if text is None:
            text = self.origText
        #print text
        QtGui.QPushButton.setText(self, text)
        if not temporary:
            self.origText = text

# Liveview functionality
        self.liveviewButton = QtGui.QPushButton('LIVEVIEW')
        self.liveviewButton.setStyleSheet("font-size:18px")
        self.liveviewButton.setCheckable(True)
        self.liveviewButton.setSizePolicy(QtGui.QSizePolicy.Preferred,
                                          QtGui.QSizePolicy.Expanding)
        self.liveviewButton.clicked.connect(self.liveview)
        self.liveviewButton.setEnabled(False)
        self.viewtimer = QtCore.QTimer()
        self.viewtimer.timeout.connect(self.updateView)

        # viewBox custom Tools
        self.gridButton = QtGui.QPushButton('Grid')
        self.gridButton.setCheckable(True)
        self.gridButton.setEnabled(False)
        self.crosshairButton = QtGui.QPushButton('Crosshair')
        self.crosshairButton.setCheckable(True)
        self.crosshairButton.setEnabled(False)

        self.flipperButton = QtGui.QPushButton('x1000')
        self.flipperButton.setStyleSheet("font-size:16px")
        self.flipperButton.setCheckable(True)
        self.flipperButton.clicked.connect(self.daq.toggleFlipper)

        self.viewCtrl = QtGui.QWidget()
        self.viewCtrlLayout = QtGui.QGridLayout()
        self.viewCtrl.setLayout(self.viewCtrlLayout)
        self.viewCtrlLayout.addWidget(self.liveviewButton, 0, 0, 1, 2)
        self.viewCtrlLayout.addWidget(self.gridButton, 1, 0)
        self.viewCtrlLayout.addWidget(self.crosshairButton, 1, 1)
        self.viewCtrlLayout.addWidget(self.flipperButton, 2, 0, 1, 2)

def makeWidget(self):

        l = self.makeLayout()

        graphIcon = QtGui.QIcon()
        graphIcon.addFile(':/images/wavelimits.png', state=QtGui.QIcon.On)
        graphIcon.addFile(':/images/wavelimitsoff.png', state=QtGui.QIcon.Off)

        self.graphBtn = QtGui.QPushButton()
        self.graphBtn.setToolTip("Allows range selection by draging the interval boundaries on the graph")
        self.graphBtn.setFixedWidth(20)
        self.graphBtn.setFixedHeight(20)
        self.graphBtn.setIcon(graphIcon)
        self.graphBtn.setCheckable(True)

        l.addWidget(QtGui.QLabel("  "))
        l.addWidget(self.graphBtn)
        l.addWidget(QtGui.QLabel("  "))

        w = QWidgetWSignals()
        w.setLayout(l)
        w.setMinimumHeight(33)

        w.sigChanged = w.sigValueChanged
        w.sigChanging = w.sigValueChanging

def buildToolbox(self):
        self.nodeToolbox = QtGui.QToolBox()
        for section, nodes in library.getNodeTree().items():
            tbwid = QtGui.QWidget()
            tbl = QtGui.QGridLayout()
            tbwid.setLayout(tbl)
            row = 0
            col = 0
            for name in nodes:
                itm = QtGui.QPushButton(name)
                itm.clicked.connect(partial(self.nodeButtonPushed, name))
                tbl.addWidget(itm, row, col)
                
                col = col + 1
                if col > 1:
                    row = row + 1
                    col = 0
                
            #tbl.addStretch()
            self.nodeToolbox.addItem(tbwid, section)
        #self.nodeMenu.triggered.connect(self.nodeMenuTriggered)
        self.nodeToolbox.setSizePolicy(QtGui.QSizePolicy.Minimum, QtGui.QSizePolicy.Minimum)
        return self.nodeToolbox

def addButton(label, widget=None, function=None):
            button = QtGui.QPushButton(label)
            if function is None:
                button.clicked.connect(lambda: widget.setVisible(widget.isHidden()))
            else:
                button.clicked.connect(function)
            button.setStyleSheet('QPushButton {'
                                 'border-color: black;'
                                 'border-width: 5px;}')
            buttonBarWidgetLayout.addWidget(button)
            return button

## first dock gets save/restore buttons
        self.t = ParameterTree()


        if params != None:
            self.p_child = Parameter.create(name='params', type='group', children=params)
            self.t.setParameters(self.p_child, showTop=False)

        self.t.setWindowTitle('pyqtgraph example: Parameter Tree')
        self.seq_cntr.addWidget(self.t)


        self.seq = pg.LayoutWidget()
        self.label = QtGui.QLabel("""Controls""")
        self.saveBtn = QtGui.QPushButton('Add Action')
        self.restoreBtn = QtGui.QPushButton('Modify table')
        self.restoreBtn.setEnabled(False)
        self.seq.addWidget(self.label, row=0, col=0)
        self.seq.addWidget(self.saveBtn, row=1, col=0)
        self.seq.addWidget(self.restoreBtn, row=2, col=0)
        self.seq_cntr.addWidget(self.seq)

params = [
            {'name': 'Basic opt. parameters', 'type': 'group', 'children': [
        {'name': 'debug', 'type': 'bool', 'value': False},
        {'name': 'logging', 'type': 'bool', 'value': True},
        {'name': 'log file', 'type': 'str', 'value': 'test.log'},
        {'name': 'timeout', 'type': 'float', 'value': 3, 'step': 0.1, 'limits': (0, 10)},
        #{'name': 'SASE det.', 'type': 'list', 'values': {'mcp': 'mcp', 'gmd slow':'gmd_fl1_slow', 'bkr':'bkr', 'default':'gmd_default'}, 'value': "default"},
        {'name': 'detector', 'type': 'list', 'values': ['gmd_default', 'mcp', 'gmd_fl1_slow', 'bkr'], 'value': "gmd_default"} ]}
        ]

        self.t_cntr = ParameterTree()
        self.p_cntr = Parameter.create(name='control', type='group', children=params)
        self.t_cntr.setParameters(self.p_cntr, showTop=False)


        self.restore_cur_btn = QtGui.QPushButton('Restore')
        #self.restore_cur_btn.setEnabled(False)
        self.setmax_opt_btn = QtGui.QPushButton('Set currents for max SASE')
        #self.setmax_opt_btn.setEnabled(False)
        self.stop_opt_btn = QtGui.QPushButton('Stop')
        self.clear_disp_btn = QtGui.QPushButton('Clear display')

        self.save_machine_btn = QtGui.QPushButton('Save new tuning')
        #self.save_machine_btn.setEnabled(False)
        #self.stop_btn = QtGui.QPushButton('stop')
        #self.w5.addWidget(self.start_opt_btm, row=0, col=0)
        self.w5.addWidget(self.stop_opt_btn, row=0, col=0)
        self.w5.addWidget(self.restore_cur_btn, row=1, col=0)
        #self.w5.addWidget(self.setmax_opt_btn, row=2, col=0)

        self.w5.addWidget(self.clear_disp_btn, row=4, col=0)