How to use the laspy.base function in laspy

self._reader = base.Reader(self.filename, mode = self._mode, header=self._header)

            if self.in_srs:
                self._reader.SetInputSRS(self.in_srs)
            if self.out_srs:
                self._reader.SetOutputSRS(self.out_srs)
            ## Wire up API for extra dimensions
            if self._reader.extra_dimensions != []:
                for dimension in self._reader.extra_dimensions:
                    dimname = dimension.name.decode().replace("\x00", "").replace(" ", "_").lower()
                    self.addProperty(dimname)


        elif self._mode == 'rw':
            if self._header is None:
                self._writer = base.Writer(self.filename,mode = self._mode)
                self._reader = self._writer
                self._header = self._reader.get_header()
                ## Wire up API for any extra Dimensions
                if self._writer.extra_dimensions != []:
                    for dimension in self._writer.extra_dimensions:
                        dimname = dimension.name.decode().replace("\x00", "").replace(" ", "_").lower()
                        self.addProperty(dimname) 
            else:
                raise util.LaspyException("Headers must currently be stored in the file, you provided: " + str(self._header))
    
        elif self._mode == 'w': 
            if self._header is None:
                raise util.LaspyException("Creation of a file in write mode requires a header object.")  
            if isinstance(self._header,  header.HeaderManager):
                vlrs = self._header.vlrs
                evlrs = self._header.evlrs

def open(self):
        '''Open the file for processing, called by __init__
        '''
       
        if self._mode in ("r", "r-"):
            if not os.path.exists(self.filename):
                raise OSError("No such file or directory: '%s'" % self.filename)
            ## Make sure we have a header
            if self._header is None:
                self._reader = base.Reader(self.filename, mode=self._mode)
                self._header = self._reader.get_header()
            else: 
                raise util.LaspyException("Headers must currently be stored in the file, you provided: " + str(self._header))
                self._reader = base.Reader(self.filename, mode = self._mode, header=self._header)

            if self.in_srs:
                self._reader.SetInputSRS(self.in_srs)
            if self.out_srs:
                self._reader.SetOutputSRS(self.out_srs)
            ## Wire up API for extra dimensions
            if self._reader.extra_dimensions != []:
                for dimension in self._reader.extra_dimensions:
                    dimname = dimension.name.decode().replace("\x00", "").replace(" ", "_").lower()
                    self.addProperty(dimname)

def open(self):
        '''Open the file for processing, called by __init__
        '''
       
        if self._mode in ("r", "r-"):
            if not os.path.exists(self.filename):
                raise OSError("No such file or directory: '%s'" % self.filename)
            ## Make sure we have a header
            if self._header is None:
                self._reader = base.Reader(self.filename, mode=self._mode)
                self._header = self._reader.get_header()
            else: 
                raise util.LaspyException("Headers must currently be stored in the file, you provided: " + str(self._header))
                self._reader = base.Reader(self.filename, mode = self._mode, header=self._header)

            if self.in_srs:
                self._reader.SetInputSRS(self.in_srs)
            if self.out_srs:
                self._reader.SetOutputSRS(self.out_srs)
            ## Wire up API for extra dimensions
            if self._reader.extra_dimensions != []:
                for dimension in self._reader.extra_dimensions:
                    dimname = dimension.name.decode().replace("\x00", "").replace(" ", "_").lower()
                    self.addProperty(dimname)


        elif self._mode == 'rw':
            if self._header is None:
                self._writer = base.Writer(self.filename,mode = self._mode)
                self._reader = self._writer