To send any file to Pythonista, select sahre and "Run Pythonista Script"

Then use this script below in Pythonista (you need to add it as an extension) to save any file from "run Pythonista Script" share method ... works with any file type .py .zip etc.

All imported file are store in a directory "inbox" in Pythonista

# coding: utf-8

import appex
import clipboard
import console
import shutil
import os

def getuniquename(filename, ext):
    root, extension = os.path.splitext(filename)
    if ext!='':
        extension = ext
    filename = root + extension
    filenum = 1
    while os.path.isfile(filename):
        filename = '{} {}{}'.format(root, filenum, extension)
        filenum += 1
    return filename

def main():
    console.clear()
    dest_path_short = '~/Documents/inbox'
    dest_path = os.path.expanduser(dest_path_short)
    if not os.path.isdir(dest_path):
        print('Create ' + dest_path_short)
        os.mkdir(dest_path) 
    if not appex.is_running_extension():
        print('Using clipboard content...')
        text = clipboard.get()
        assert text, 'No text on the clipboard!'
        resp = console.alert('Alert!', 'Choose File Extension', '.py', '.pyui', hide_cancel_button=False)
        if resp==1:
            ext = '.py'
        elif resp==2:
            ext = '.pyui'
        filename=os.path.join(dest_path,'clipboard')
        filename=getuniquename(filename,ext)
        while os.path.isfile(filename):
            filename = '{} {}{}'.format(root, filenum, extension)
            filenum += 1
        with open(filename,'w') as f:
            f.write(text)
        print('Done!')      
    else:
        file = appex.get_file_path()    
        print('Input path: %s' % file)
        filename=os.path.join(dest_path, os.path.basename(file))
        filename=getuniquename(filename,'')
        shutil.copy(file,filename)
    print('Saved in %s' % dest_path_short)
    if not os.path.exists(filename):
        print(' > Error file %s not found !' % os.path.basename(filename))
    else:
        print(' > as %s' % os.path.basename(filename))

if __name__ == '__main__':
    main()

Use "File Transfer" app to transfer file between devices.
To send a script to "File Transfer" from Pythonista use "Share" and "Open In" to import in File transfer.
To open a script from "File Transfer" to Pythonista, use "To other app" in "File Transfer" and on the bottom list select "Run Pythonista Script"

Then use this script in Pythonista to save any file from the previous "run Pythonista Script"

# coding: utf-8

import appex
import clipboard
import console
import shutil
import os

def getuniquename(filename, ext):
    root, extension = os.path.splitext(filename)
    if ext!='':
        extension = ext
    filename = root + extension
    filenum = 1
    while os.path.isfile(filename):
        filename = '{} {}{}'.format(root, filenum, extension)
        filenum += 1
    return filename

def main():
    console.clear()
    dest_path_short = '~/Documents/inbox'
    dest_path = os.path.expanduser(dest_path_short)
    if not os.path.isdir(dest_path):
        print('Create ' + dest_path_short)
        os.mkdir(dest_path) 
    if not appex.is_running_extension():
        print('Using clipboard content...')
        text = clipboard.get()
        assert text, 'No text on the clipboard!'
        resp = console.alert('Alert!', 'Choose File Extension', '.py', '.pyui', hide_cancel_button=False)
        if resp==1:
            ext = '.py'
        elif resp==2:
            ext = '.pyui'
        filename=os.path.join(dest_path,'clipboard')
        filename=getuniquename(filename,ext)
        while os.path.isfile(filename):
            filename = '{} {}{}'.format(root, filenum, extension)
            filenum += 1
        with open(filename,'w') as f:
            f.write(text)
        print('Done!')      
    else:
        file = appex.get_file_path()    
        print('Input path: %s' % file)
        filename=os.path.join(dest_path, os.path.basename(file))
        filename=getuniquename(filename,'')
        shutil.copy(file,filename)
    print('Saved in %s' % dest_path_short)
    if not os.path.exists(filename):
        print(' > Error file %s not found !' % os.path.basename(filename))
    else:
        print(' > as %s' % os.path.basename(filename))

if __name__ == '__main__':
    main()