diff --git a/src/favicon/favicon.py b/src/favicon/favicon.py
index d74471b..fcf0638 100644
--- a/src/favicon/favicon.py
+++ b/src/favicon/favicon.py
@@ -124,7 +124,7 @@ def tags(url, html):
 
     icons = set()
     for tag in link_tags | meta_tags:
-        href = tag.get('href') or tag.get('content')
+        href = tag.get('href', '') or tag.get('content', '')
         href = href.strip()
 
         if not href or href.startswith('data:image/'):

'NoneType' object has no attribute 'strip'
Hi, thanks for this awesome egg :)

I think that I found a bug when a [website](https://aol.com/) contains this meta: `<link href="" rel="shortcut icon"/>` .

This causes `tag.get('href') or tag.get('content')` at favicon.py to return `None` instead of a string.

You may want to not include metas with empty href/content into the one to parse :blush: 

Thank you in advance for your time and I wish you a great week :)

diff --git a/tests/test_favicon.py b/tests/test_favicon.py
index 0fec2f2..96f4cf3 100644
--- a/tests/test_favicon.py
+++ b/tests/test_favicon.py
@@ -116,6 +116,16 @@ def test_link_tag_href_attribute(m, link, url):
     assert icon.url == url
 
 
+def test_link_tag_empty_href_attribute(m):
+    """'NoneType' object has no attribute 'strip' #22"""
+    m.get('http://mock.com/', text='<link rel="icon" href="">')
+
+    with pytest.warns(None):
+        icons = favicon.get('http://mock.com/')
+
+    assert not icons
+
+
 @pytest.mark.parametrize(
     'meta_tag',
     [
@@ -143,6 +153,7 @@ def test_invalid_meta_tag(m):
 
 
 def test_request_kwargs(m):
+    """Add request timeout #21"""
     headers = {
         'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0'
     }

pip install -e .
parse_log_pytest
pytest
pytest requests-mock
3.6
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
attrs @ file:///opt/conda/conda-bld/attrs_1642510447205/work
beautifulsoup4==4.12.3
certifi==2021.5.30
charset-normalizer==2.0.12
-e git+https://github.com/scottwernervt/favicon.git@eb9f0d21a87814ab0b41bd7f2f47fcac0f47ccfb#egg=favicon
idna==3.10
importlib-metadata @ file:///tmp/build/80754af9/importlib-metadata_1631916693255/work
iniconfig @ file:///home/linux1/recipes/ci/iniconfig_1610983019677/work
more-itertools @ file:///tmp/build/80754af9/more-itertools_1637733554872/work
packaging @ file:///tmp/build/80754af9/packaging_1637314298585/work
pluggy @ file:///tmp/build/80754af9/pluggy_1615976315926/work
py @ file:///opt/conda/conda-bld/py_1644396412707/work
pyparsing @ file:///tmp/build/80754af9/pyparsing_1635766073266/work
pytest==6.2.4
requests==2.27.1
requests-mock==1.12.1
soupsieve==2.3.2.post1
toml @ file:///tmp/build/80754af9/toml_1616166611790/work
typing_extensions @ file:///opt/conda/conda-bld/typing_extensions_1647553014482/work
urllib3==1.26.20
zipp @ file:///tmp/build/80754af9/zipp_1633618647012/work

name: favicon
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - attrs=21.4.0=pyhd3eb1b0_0
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2021.5.30=py36h06a4308_0
  - importlib-metadata=4.8.1=py36h06a4308_0
  - importlib_metadata=4.8.1=hd3eb1b0_0
  - iniconfig=1.1.1=pyhd3eb1b0_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.3=he6710b0_2
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - more-itertools=8.12.0=pyhd3eb1b0_0
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - packaging=21.3=pyhd3eb1b0_0
  - pip=21.2.2=py36h06a4308_0
  - pluggy=0.13.1=py36h06a4308_0
  - py=1.11.0=pyhd3eb1b0_0
  - pyparsing=3.0.4=pyhd3eb1b0_0
  - pytest=6.2.4=py36h06a4308_2
  - python=3.6.13=h12debd9_1
  - readline=8.2=h5eee18b_0
  - setuptools=58.0.4=py36h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - toml=0.10.2=pyhd3eb1b0_0
  - typing_extensions=4.1.1=pyh06a4308_0
  - wheel=0.37.1=pyhd3eb1b0_0
  - xz=5.6.4=h5eee18b_1
  - zipp=3.6.0=pyhd3eb1b0_0
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - beautifulsoup4==4.12.3
      - charset-normalizer==2.0.12
      - idna==3.10
      - requests==2.27.1
      - requests-mock==1.12.1
      - soupsieve==2.3.2.post1
      - urllib3==1.26.20
prefix: /opt/conda/envs/favicon

tests/test_favicon.py::test_link_tag_empty_href_attribute
tests/test_favicon.py::test_default tests/test_favicon.py::test_link_tag[icon] tests/test_favicon.py::test_link_tag[ICON tests/test_favicon.py::test_link_tag[shortcut tests/test_favicon.py::test_link_tag[apple-touch-icon] tests/test_favicon.py::test_link_tag[apple-touch-icon-precomposed] tests/test_favicon.py::test_link_tag_sizes_attribute[any] tests/test_favicon.py::test_link_tag_sizes_attribute[16x16] tests/test_favicon.py::test_link_tag_sizes_attribute[24x24+] tests/test_favicon.py::test_link_tag_sizes_attribute[32x32 tests/test_favicon.py::test_link_tag_sizes_attribute[64x64 tests/test_favicon.py::test_link_tag_sizes_attribute[logo-128x128.png] tests/test_favicon.py::test_link_tag_sizes_attribute[new tests/test_favicon.py::test_link_tag_href_attribute[filename] tests/test_favicon.py::test_link_tag_href_attribute[filename tests/test_favicon.py::test_link_tag_href_attribute[relative] tests/test_favicon.py::test_link_tag_href_attribute[https] tests/test_favicon.py::test_link_tag_href_attribute[forward tests/test_favicon.py::test_link_tag_href_attribute[query tests/test_favicon.py::test_meta_tag[msapplication-TileImage] tests/test_favicon.py::test_meta_tag[msapplication-tileimage] tests/test_favicon.py::test_meta_tag[og:image] tests/test_favicon.py::test_invalid_meta_tag tests/test_favicon.py::test_request_kwargs tests/test_favicon.py::test_is_absolute_helper[http://mock.com/favicon.ico-True] tests/test_favicon.py::test_is_absolute_helper[favicon.ico-False] tests/test_favicon.py::test_is_absolute_helper[/favicon.ico-False]
src/favicon/favicon.py
src/favicon/favicon.py