Using this code:

from matplotlib.dates import DateFormatter

date_fmt = "%H:%M:%S"
date_formatter = DateFormatter(date_fmt)

Running Mypy in strict mode results in an erorr:

$ mypy --strict main.py 
main.py:4: error: Call to untyped function "DateFormatter" in typed context  [no-untyped-call]
Found 1 error in 1 file (checked 1 source file)

We run Mypy in strict mode across all of our code base to catch programming errors and would like to use it with matplotlib without the need to suppress errors like this.

Environment

• Python 3.11.11
• matplotlib 3.10.1
• mypy 1.15.0

Related References

• Support type checking with mypy #20504
• Initial implementation of type stubs (mypy/PEP484) #24976