Find all .py files that import a certain module or just supplied methods of the module. I use http://click.pocoo.org/ for interacting with the command line, but this can be changed.

imports.py

import os
import re

from subprocess import PIPE, Popen

import click


def which(executable):    
    for path in os.environ['PATH'].split(os.pathsep):
        path = path.strip('"')

        fpath = os.path.join(path, executable)

        if os.path.isfile(fpath) and os.access(fpath, os.X_OK):
            return fpath

    if os.name == 'nt' and not executable.endswith('.exe'):
        return which('{}.exe'.format(executable))

    return None


def find_files(pattern, path, exts=('.py')):
    pattern = re.compile(pattern)
    found = []
    path = os.path.realpath(path)
    for root, dirnames, files in os.walk(path):
        for fname in files:
            if fname.endswith(exts):
                with open(os.path.join(root, fname), 'r') as f:
                    if any(pattern.search(line) for line in f):
                        found.append(os.path.join(root, fname))
                        break
    return sorted(found)


def grep_files(pattern, path, exts=('.py')):
    path = os.path.realpath(path)
    grep = '''grep -E "{}" * -lr'''.format(pattern)

    proc = Popen(grep, shell=True, cwd=path, stdout=PIPE, stderr=PIPE)

    out, err = proc.communicate()

    if err:
        print err

    if not out:
        return None

    out = out.decode('utf8')
    found = []
    for f in out.split():
        if f.endswith(exts):
            found.append(os.path.join(path, f.replace('/', os.sep)))

    return sorted(found)


def find_module(module, path, methods=[]):
    if len(methods) != 0:
        pattern = ''
        i = 0
        for method in methods:
            pattern += '''from {} import {}'''.format(module, method)
            if i < len(methods) - 1:
                pattern += '|'
            i += 1
    else:
        pattern = '''import {0}|from {0}'''.format(module)

    if which('grep'):
        return grep_files(pattern, path)

    return find_files(pattern, path)


@click.command()
@click.argument('module')
@click.option('--path', '-p', default='./', help='project path')
@click.option('--methods', '-m', multiple=True, help='method imported')
def module_finder(module, path, methods):
    click.clear()
    click.echo('searching {} for imports of...\n'.format(os.path.realpath(path)))
    if methods:
        click.echo(' OR\n'.join(['  {}.{}'.format(module, m) for m in methods]))

    else:
        click.echo('  {}'.format(module))

    click.echo('')
    click.echo('-' * 80)
    click.echo('')

    files = find_module(module, path, methods)
    if files:
        for f in files:
            click.echo(f)
    else:
        click.echo('no files found.')

    click.echo('')
    click.echo('-' * 80)

if __name__ == '__main__':
    module_finder()


'''
c:\projects\python\sandbox>imports.py fontaispy.numbers.stubs -m ceil -m gcd

searching c:\projects\python\sandbox for imports of...

  fontaispy.numbers.stubs.ceil OR
  fontaispy.numbers.stubs.gcd

--------------------------------------------------------------------------------

c:\projects\python\sandbox\fontaispy\benchmark.py
c:\projects\python\sandbox\fontaispy\numbers\primes.py

--------------------------------------------------------------------------------

c\projects\python\sandbox>
'''