nmap doesnot scan the network proerply

Question

I have the below script which was originally added with networkscan, but i did change the scanner to nmap and below is my code. when i execute the script, the script doesnot throw me any error and it executes successfully, But it says "no host found in network" and doesnot scan anything. can anyone suggest me what is wrong.

import pynetbox, urllib3, nmap, socket, ipaddress
from extras.scripts import *

TOKEN='token'
NETBOXURL='https://example.com'

urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning) #disable safety warnings

class IpScan(Script):
    #optional variables in UI here!
    TagBasedScanning = BooleanVar(
        label="Tag Based Scanning?",
        default=False,
        description="enable Tag Based Scanning, to scan only Subnets with specified Tag.",
    )
    tag = StringVar(
         max_length=20,
         label="Scan Tag?",
         default="Scan",
         description="specify the Tag to filter Subnets to be scanned",
         required=True,
    )


    class Meta:
        name = "IP Scanner"
        description = "Scans available prefixes and updates ip addresses in IPAM Module"


    def run(self, data, commit):

        def reverse_lookup(ip):
            '''
            Mini function that does DNS reverse lookup with controlled failure
            '''
            try:
                data = socket.gethostbyaddr(ip)
            except Exception:
                return '' #fails gracefully
            if data[0] == '': #if there is no name
                return ''
            else:
                return data[0]

        nb = pynetbox.api(NETBOXURL, token=TOKEN)
        nb.http_session.verify = False #disable certificate checking

        subnets = nb.ipam.prefixes.all() #extracts all prefixes, in format x.x.x.x/yy

        for subnet in subnets:
            if data['TagBasedScanning'] and data['tag'] not in str(subnet.tags): # Only scan subnets with the Tag
                self.log_debug(f'checking {subnet}...Tag is {subnet.tags}')
                self.log_warning(f"Scan of {subnet.prefix} NOT done (missing '{data['tag']}' tag)")
                continue
            if str(subnet.status) == 'Reserved': #Do not scan reserved subnets
                self.log_warning(f"Scan of {subnet.prefix} NOT done (is Reserved)")
                continue
            self.log_debug(f'checking {subnet}...Tag is {subnet.tags}')
            IPv4network = ipaddress.IPv4Network(subnet)
            mask = '/'+str(IPv4network.prefixlen)
            nm = nmap.PortScanner()
            nm.scan(hosts='subnet', arguments='-n -sP')
            list_of_hosts_found = [(x, nm[x]['status']['state']) for x in nm.all_hosts()]
#            for host, status in lists_of_hosts_found:
            print (host)
            self.log_info(f'Scan of {subnet} done.')

            #Routine to mark as DEPRECATED each Netbox entry that does not respond to ping
            for address in IPv4network.hosts(): #for each address of the prefix x.x.x.x/yy...
                        #self.log_debug(f'checking {address}...')
                netbox_address = nb.ipam.ip_addresses.get(address=address) #extract address info from Netbox
                if netbox_address != None: #if the ip exists in netbox // if none exists, leave it to discover
                    if str(netbox_address).rpartition('/')[0] in list_of_hosts_found: #if he is in the list of "alive"
                        pass #do nothing: It exists in NB and is in the pinged list: ok continue, you will see it later when you cycle the ip addresses that have responded whether to update something
                                    #self.log_success(f"The host {str(netbox_address).rpartition('/')[0]} exists in netbox and has been pinged")
                    else: #if it exists in netbox but is NOT in the list, mark it as deprecated
                        if str(netbox_address.status) == 'Deprecated' or str(netbox_address.status) == 'Reserved': #check the ip address to be Deprecated or Reserved
                            pass # leave it as is
                        else:
                            self.log_warning(f"Host {str(netbox_address)} exists in netbox but not responding --> deprecated")
                            nb.ipam.ip_addresses.update([{'id':netbox_address.id, 'status':'deprecated'},])
            ####

            if  list_of_hosts_found == []:
                self.log_warning(f'No host found in network {subnet}')
            else:
                self.log_success(f'IPs found: {list_of_hosts_found}')
            for address1 in list_of_hosts_found: #for each ip in the ping list...
                ip_mask=str(address1)+mask
                current_in_netbox = nb.ipam.ip_addresses.get(address=ip_mask) #extract current data in Netbox related to ip
                #self.log_debug(f'pinged ip: {address1} mask: {mask} --> {ip_mask} // extracted ip from netbox: {current_in_netbox}')
                if current_in_netbox != None: #the pinged address is already present in the Netbox, mark it as Active and check the name if it has changed
                    nb.ipam.ip_addresses.update([{'id':current_in_netbox.id, 'status':'active'},])
                    name = reverse_lookup(address1) #name resolution from DNS
                    if current_in_netbox.dns_name == name: #the names in Netbox and DNS match, do nothing
                        pass
                    else: #the names in Netbox and in DNS *DO NOT* match --> update Netbox with DNS name
                        self.log_success(f'Name for {address1} updated to {name}')
                        nb.ipam.ip_addresses.update([{'id':current_in_netbox.id, 'dns_name':name},])
                else: #the pinged address is NOT present in Netbox, I have to add it
                    name = reverse_lookup(address1) #name resolution from DNS
                    res = nb.ipam.ip_addresses.create(address=ip_mask, status='active', dns_name=name)
                    if res:
                        self.log_success(f'Added {address1} - {name}')
                    else:
                        self.log_error(f'Adding {address1} - {name} FAILED')

Is it feasible to do with nmap . If yes how can i achieve it.