pandas.ExcelWriter has abstract methods
#### Code Sample, a copy-pastable example if possible

```python
"""Lorem ipsum"""

import pandas as pd


def demo():
    """Demo for the false positive"""
    with pd.ExcelWriter("demo.xlsx") as writer:
        print(writer)
```



#### Problem description

The code shown above gives pylint: ``abstract-class-instantiated(E0110): test.py:8:9: demo: Abstract class 'ExcelWriter' with abstract methods instantiated``

#### Expected Output

No pylint issue: no abstract method left

#### Output of ``pd.show_versions()``


<details>

```
INSTALLED VERSIONS
------------------
commit           : None
python           : 3.7.4.final.0
python-bits      : 64
OS               : Linux
OS-release       : 4.15.0-54-generic
machine          : x86_64
processor        : x86_64
byteorder        : little
LC_ALL           : None
LANG             : en_US.UTF-8
LOCALE           : en_US.UTF-8

pandas           : 0.25.0
numpy            : 1.16.4
pytz             : 2019.1
dateutil         : 2.8.0
pip              : 19.2.1
setuptools       : 40.8.0
Cython           : 0.29.12
pytest           : 5.0.1
hypothesis       : None
sphinx           : None
blosc            : None
feather          : None
xlsxwriter       : 1.1.8
lxml.etree       : 4.3.4
html5lib         : None
pymysql          : None
psycopg2         : 2.8.3 (dt dec pq3 ext lo64)
jinja2           : 2.10.1
IPython          : 7.6.1
pandas_datareader: None
bs4              : 4.8.0
bottleneck       : 1.2.1
fastparquet      : None
gcsfs            : None
lxml.etree       : 4.3.4
matplotlib       : 3.1.1
numexpr          : 2.6.9
odfpy            : None
openpyxl         : None
pandas_gbq       : None
pyarrow          : None
pytables         : None
s3fs             : None
scipy            : 1.3.0
sqlalchemy       : None
tables           : None
xarray           : None
xlrd             : 1.2.0
xlwt             : None
xlsxwriter       : 1.1.8

```
</details>
